(svn r22252) [1.1] -Backport from trunk:

- Fix: Do not resort town, industry and signs list directly in OnInvalidateData(). There might be a scheduled rebuild which needs execution first. So, only set a trigger for resorting [FS#4546] (r22249, r22248, r22247, r22246, r22245, r22244, r22243, r22242, r22241, r22236, r22228, r22227, r22226)

src/ai/ai_gui.cpp

@@ -182,13 +182,20 @@ struct AIListWindow : public Window {
 		nwi->widget_data = (this->vscroll->GetCapacity() << MAT_ROW_START) + (1 << MAT_COL_START);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (_game_mode == GM_NORMAL && Company::IsValidID(this->slot)) {
 			delete this;
 			return;
 		}
 
+		if (!gui_scope) return;
+
 		this->vscroll->SetCount((int)this->ai_info_list->size() + 1);
 
 		/* selected goes from -1 .. length of ai list - 1. */
@@ -437,7 +444,12 @@ struct AISettingsWindow : public Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (_game_mode == GM_NORMAL && Company::IsValidID(this->slot)) delete this;
 	}
@@ -692,12 +704,19 @@ struct AIConfigWindow : public Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (!IsEditable(this->selected_slot)) {
 			this->selected_slot = INVALID_COMPANY;
 		}
 
+		if (!gui_scope) return;
+
 		this->SetWidgetDisabledState(AIC_WIDGET_DECREASE, GetGameSettings().difficulty.max_no_competitors == 0);
 		this->SetWidgetDisabledState(AIC_WIDGET_INCREASE, GetGameSettings().difficulty.max_no_competitors == MAX_COMPANIES - 1);
 		this->SetWidgetDisabledState(AIC_WIDGET_CHANGE, this->selected_slot == INVALID_COMPANY);
@@ -1032,11 +1051,16 @@ struct AIDebugWindow : public QueryStringBaseWindow {
 		return state;
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == -1 || ai_debug_company == data) this->SetDirty();
 
-		if (data == -2) {
+		if (gui_scope && data == -2) {
 			/* The continue button should be disabled when the game is unpaused and
 			 * it was previously paused by the break string ( = a line in the log
 			 * was highlighted )*/
@@ -1048,8 +1072,9 @@ struct AIDebugWindow : public QueryStringBaseWindow {
 			}
 		}
 
-		/* If the log message is related to the active company tab, check the break string */
+		/* If the log message is related to the active company tab, check the break string.
-		if (data == ai_debug_company && this->break_check_enabled && !StrEmpty(this->edit_str_buf)) {
+		 * This needs to be done in gameloop-scope, so the AI is suspended immediately. */
+		if (!gui_scope && data == ai_debug_company && this->break_check_enabled && !StrEmpty(this->edit_str_buf)) {
 			/* Get the log instance of the active company */
 			Backup<CompanyByte> cur_company(_current_company, ai_debug_company, FILE_LINE);
 			AILog::LogData *log = (AILog::LogData *)AIObject::GetLogPointer();

src/ai/api/ai_log.cpp

@@ -75,7 +75,7 @@
 
 	/* Also still print to debug window */
 	DEBUG(ai, level, "[%d] [%c] %s", (uint)_current_company, logc, log->lines[log->pos]);
-	InvalidateWindowData(WC_AI_DEBUG, 0, _current_company, true); // breakpoint handling needs calling Invalidate immediately.
+	InvalidateWindowData(WC_AI_DEBUG, 0, _current_company);
 }
 
 /* static */ void AILog::FreeLogPointer()

src/autoreplace_gui.cpp

@@ -491,9 +491,15 @@ public:
 				this->GetWidget<NWidgetCore>(RVW_WIDGET_RIGHT_MATRIX)->widget_data = (this->vscroll[0]->GetCapacity() << MAT_ROW_START) + (1 << MAT_COL_START);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data != 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->engines[0].ForceRebuild();
 		} else {
 			this->engines[1].ForceRebuild();

src/build_vehicle_gui.cpp

@@ -1218,8 +1218,14 @@ struct BuildVehicleWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* When switching to original acceleration model for road vehicles, clear the selected sort criteria if it is not available now. */
 		if (this->vehicle_type == VEH_ROAD &&
 				_settings_game.vehicle.roadveh_acceleration_model == AM_ORIGINAL &&

src/company_gui.cpp

@@ -800,8 +800,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetsDisabledState(true, SCLW_WIDGET_CLASS_RAIL, SCLW_WIDGET_CLASS_ROAD, SCLW_WIDGET_CLASS_SHIP, SCLW_WIDGET_CLASS_AIRCRAFT, WIDGET_LIST_END);
 
 		bool current_class_valid = this->livery_class == LC_OTHER;

src/depot_gui.cpp

@@ -635,7 +635,12 @@ struct DepotWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		this->generate_list = true;
 	}

src/dock_gui.cpp

@@ -119,8 +119,14 @@ struct BuildDocksToolbarWindow : Window {
 		if (_settings_client.gui.link_terraform_toolbar) DeleteWindowById(WC_SCEN_LAND_GEN, 0, false);
 	}
 
-	void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetsDisabledState(!CanBuildVehicleInfrastructure(VEH_SHIP),
 			DTW_DEPOT,
 			DTW_STATION,

src/fios_gui.cpp

@@ -659,17 +659,24 @@ public:
 		this->vscroll->SetCapacityFromWidget(this, SLWW_DRIVES_DIRECTORIES_LIST);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		switch (data) {
 			case 0:
 				/* Rescan files */
 				this->selected = NULL;
 				_load_check_data.Clear();
+				if (!gui_scope) break;
 				BuildFileList();
 				/* FALL THROUGH */
 			case 1:
 				/* Selection changes */
+				if (!gui_scope) break;
 				if (_saveload_mode == SLD_LOAD_GAME || _saveload_mode == SLD_LOAD_SCENARIO) {
 					this->SetWidgetDisabledState(SLWW_LOAD_BUTTON,
 							this->selected == NULL || _load_check_data.HasErrors() || !(_load_check_data.grf_compatibility != GLC_NOT_FOUND || _settings_client.gui.UserIsAllowedToChangeNewGRFs()));

src/genworld_gui.cpp

@@ -425,8 +425,14 @@ struct GenerateLandscapeWindow : public QueryStringBaseWindow {
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Update the climate buttons */
 		this->SetWidgetLoweredState(GLAND_TEMPERATE, _settings_newgame.game_creation.landscape == LT_TEMPERATE);
 		this->SetWidgetLoweredState(GLAND_ARCTIC,    _settings_newgame.game_creation.landscape == LT_ARCTIC);

src/graph_gui.cpp

@@ -91,8 +91,14 @@ struct GraphLegendWindow : Window {
 		InvalidateWindowData(WC_COMPANY_VALUE, 0);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (Company::IsValidID(data)) return;
 
 		SetBit(_legend_excluded_companies, data);
@@ -543,8 +549,14 @@ public:
 		this->UpdateStatistics(false);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->UpdateStatistics(true);
 	}
 
@@ -1013,8 +1025,14 @@ struct PaymentRatesGraphWindow : BaseGraphWindow {
 		/* Override default OnTick */
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->OnHundredthTick();
 	}
 
@@ -1247,9 +1265,15 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->companies.ForceRebuild();
 		} else {
 			this->companies.ForceResort();
@@ -1488,11 +1512,13 @@ struct PerformanceRatingDetailWindow : Window {
 	}
 
 	/**
-	 * Invalidate the data of this window.
+	 * Some data on this window has become invalid.
 	 * @param data the company ID of the company that is going to be removed
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
 	 */
-	virtual void OnInvalidateData(int data)
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Disable the companies who are not active */
 		for (CompanyID i = COMPANY_FIRST; i < MAX_COMPANIES; i++) {
 			this->SetWidgetDisabledState(i + PRW_COMPANY_FIRST, !Company::IsValidID(i));

src/group_gui.cpp

@@ -253,9 +253,15 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->vehicles.ForceRebuild();
 			this->groups.ForceRebuild();
 		} else {
@@ -263,6 +269,7 @@ public:
 			this->groups.ForceResort();
 		}
 
+		/* Process ID-invalidation in command-scope as well */
 		if (this->group_rename != INVALID_GROUP && !Group::IsValidID(this->group_rename)) {
 			DeleteWindowByClass(WC_QUERY_STRING);
 			this->group_rename = INVALID_GROUP;

src/industry_gui.cpp

@@ -597,8 +597,14 @@ public:
 		this->RaiseButtons();
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetupArrays();
 
 		const IndustrySpec *indsp = (this->selected_type == INVALID_INDUSTRYTYPE) ? NULL : GetIndustrySpec(this->selected_type);
@@ -947,8 +953,14 @@ public:
 		this->SetDirty();
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		const Industry *i = Industry::Get(this->window_number);
 		if (IsProductionAlterable(i)) {
 			const IndustrySpec *ind = GetIndustrySpec(i->type);
@@ -1334,20 +1346,31 @@ public:
 		this->vscroll->SetCapacityFromWidget(this, IDW_INDUSTRY_LIST);
 	}
 
+	virtual void OnPaint()
+	{
+		if (this->industries.NeedRebuild()) this->BuildSortIndustriesList();
+		this->DrawWidgets();
+	}
+
 	virtual void OnHundredthTick()
 	{
 		this->industries.ForceResort();
 		this->BuildSortIndustriesList();
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->industries.ForceRebuild();
 		} else {
 			this->industries.ForceResort();
 		}
-		this->BuildSortIndustriesList();
 	}
 };
 
@@ -2386,13 +2409,15 @@ struct IndustryCargoesWindow : public Window {
 	}
 
 	/**
-	 * Notify the window about external events.
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
 	 * - data = 0 .. NUM_INDUSTRYTYPES - 1: Display the chain around the given industry.
 	 * - data = NUM_INDUSTRYTYPES: Stop sending updates to the smallmap window.
-	 * @param data The event.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
 	 */
-	virtual void OnInvalidateData(int data)
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (data == NUM_INDUSTRYTYPES) {
 			if (this->IsWidgetLowered(ICW_NOTIFY)) {
 				this->RaiseWidget(ICW_NOTIFY);

src/intro_gui.cpp

@@ -55,8 +55,14 @@ struct SelectGameWindow : public Window {
 		this->OnInvalidateData();
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetLoweredState(SGI_TEMPERATE_LANDSCAPE, _settings_newgame.game_creation.landscape == LT_TEMPERATE);
 		this->SetWidgetLoweredState(SGI_ARCTIC_LANDSCAPE,    _settings_newgame.game_creation.landscape == LT_ARCTIC);
 		this->SetWidgetLoweredState(SGI_TROPIC_LANDSCAPE,    _settings_newgame.game_creation.landscape == LT_TROPIC);

src/main_gui.cpp

@@ -432,8 +432,14 @@ struct MainWindow : Window
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Forward the message to the appropiate toolbar (ingame or scenario editor) */
 		InvalidateWindowData(WC_MAIN_TOOLBAR, 0, data, true);
 	}

src/misc_gui.cpp

@@ -331,8 +331,14 @@ public:
 		::ShowNewGRFInspectWindow(GetGrfSpecFeature(this->tile), this->tile);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		switch (data) {
 			case 1:
 				/* ReInit, "debug" sprite might have changed */
@@ -638,7 +644,12 @@ public:
 		return pt;
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		/* If company gets shut down, while displaying an error about it, remove the error message. */
 		if (this->face != INVALID_COMPANY && !Company::IsValidID(this->face)) delete this;

src/music_gui.cpp

@@ -312,8 +312,14 @@ struct MusicTrackSelectionWindow : public Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		for (int i = 0; i < 6; i++) {
 			this->SetWidgetLoweredState(MTSW_ALL + i, i == _msf.playlist);
 		}
@@ -637,8 +643,14 @@ struct MusicWindow : public Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		for (int i = 0; i < 6; i++) {
 			this->SetWidgetLoweredState(MW_ALL + i, i == _msf.playlist);
 		}

src/network/network_chat_gui.cpp

@@ -531,7 +531,12 @@ struct NetworkChatWindow : public QueryStringBaseWindow {
 		ShowOnScreenKeyboard(this, wid, NWCW_CLOSE, NWCW_SENDBUTTON);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == this->dest) delete this;
 	}

src/network/network_content_gui.cpp

@@ -751,8 +751,14 @@ public:
 		this->InvalidateData();
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (this->content.NeedRebuild()) this->BuildContentList();
 
 		/* To sum all the bytes we intend to download */

src/network/network_gui.cpp

@@ -794,7 +794,12 @@ public:
 		if (this->field == NGWW_CLIENT) this->HandleEditBox(NGWW_CLIENT);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == 1) {
 			this->server = NULL;

src/newgrf_debug_gui.cpp

@@ -772,8 +772,14 @@ struct SpriteAlignerWindow : Window {
 		this->SetDirty();
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (data == 1) {
 			/* Sprite picker finished */
 			this->RaiseWidget(SAW_PICKER);

src/newgrf_gui.cpp

@@ -379,8 +379,14 @@ struct NewGRFParametersWindow : public Window {
 		nwi->widget_data = (this->vscroll->GetCapacity() << MAT_ROW_START) + (1 << MAT_COL_START);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (!this->action14present) {
 			this->SetWidgetDisabledState(GRFPAR_WIDGET_NUMPAR_DEC, this->grf_config->num_params == 0);
 			this->SetWidgetDisabledState(GRFPAR_WIDGET_NUMPAR_INC, this->grf_config->num_params >= this->grf_config->num_valid_params);
@@ -1025,15 +1031,18 @@ struct NewGRFWindow : public QueryStringBaseWindow {
 	}
 
 	/**
-	 * Calback to update internal data.
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
 	 *  - 0: (optionally) build availables, update button status.
 	 *  - 1: build availables, Add newly found grfs, update button status.
 	 *  - 2: (optionally) build availables, Reset preset, + 3
 	 *  - 3: (optionally) build availables, Update active scrollbar, update button status.
 	 *  - 4: Force a rebuild of the availables, + 2
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
 	 */
-	virtual void OnInvalidateData(int data = 0)
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		switch (data) {
 			default: NOT_REACHED();
 			case 0:

src/news_gui.cpp

@@ -498,8 +498,14 @@ struct NewsWindow : Window {
 		return ES_NOT_HANDLED;
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* The chatbar has notified us that is was either created or closed */
 		int newtop = this->top + this->chat_height - data;
 		this->chat_height = data;
@@ -1035,8 +1041,14 @@ struct MessageHistoryWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->vscroll->SetCount(_total_news);
 	}
 
@@ -1201,8 +1213,14 @@ struct MessageOptionsWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Update the dropdown value for 'set all categories'. */
 		this->GetWidget<NWidgetCore>(WIDGET_NEWSOPT_DROP_SUMMARY)->widget_data = this->message_opt[this->state];
 

src/order_gui.cpp

@@ -805,13 +805,18 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
-		VehicleOrderID from = GB(data, 0, 8);
+		VehicleOrderID from = INVALID_VEH_ORDER_ID;
-		VehicleOrderID to   = GB(data, 8, 8);
+		VehicleOrderID to   = INVALID_VEH_ORDER_ID;
 
 		switch (data) {
-			case 0:
+			case -666:
 				/* Autoreplace replaced the vehicle */
 				this->vehicle = Vehicle::Get(this->window_number);
 				break;
@@ -830,6 +835,11 @@ public:
 				break;
 
 			default:
+				if (data < 0) break;
+
+				if (gui_scope) break; // only do this once; from command scope
+				from = GB(data, 0, 8);
+				to   = GB(data, 8, 8);
 				/* Moving an order. If one of these is INVALID_VEH_ORDER_ID, then
 				 * the order is being created / removed */
 				if (this->selected_order == -1) break;
@@ -859,7 +869,7 @@ public:
 		}
 
 		this->vscroll->SetCount(this->vehicle->GetNumOrders() + 1);
-		this->UpdateButtonState();
+		if (gui_scope) this->UpdateButtonState();
 
 		/* Scroll to the new order. */
 		if (from == INVALID_VEH_ORDER_ID && to != INVALID_VEH_ORDER_ID && !this->vscroll->IsVisible(to)) {

src/osk_gui.cpp

@@ -247,8 +247,14 @@ struct OskWindow : public Window {
 		this->parent->SetWidgetDirty(this->text_btn);
 	}
 
-	virtual void OnInvalidateData(int)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetDirty(OSK_WIDGET_TEXT);
 	}
 };

src/rail_gui.cpp

@@ -1617,8 +1617,14 @@ public:
 		this->InvalidateData();
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->LowerWidget((_cur_signal_variant == SIG_ELECTRIC ? BSW_ELECTRIC_NORM : BSW_SEMAPHORE_NORM) + _cur_signal_type);
 
 		this->SetWidgetLoweredState(BSW_CONVERT, _convert_signal_button);

src/road_gui.cpp

@@ -341,8 +341,14 @@ struct BuildRoadToolbarWindow : Window {
 		if (_settings_client.gui.link_terraform_toolbar) DeleteWindowById(WC_SCEN_LAND_GEN, 0, false);
 	}
 
-	void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetsDisabledState(!CanBuildVehicleInfrastructure(VEH_ROAD),
 				RTW_DEPOT,
 				RTW_BUS_STATION,

src/settings_gui.cpp

@@ -460,8 +460,14 @@ struct GameOptionsWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->SetWidgetLoweredState(GOW_FULLSCREEN_BUTTON, _fullscreen);
 
 		bool missing_files = BaseGraphics::GetUsedSet()->GetNumMissing() == 0;
@@ -724,8 +730,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		uint i;
 		const SettingDesc *sd = GetSettingFromName("difficulty.max_no_competitors", &i);
 		for (i = 0; i < GAME_DIFFICULTY_NUM; i++, sd++) {

src/signs_gui.cpp

@@ -164,9 +164,7 @@ struct SignListWindow : QueryStringBaseWindow, SignList {
 		/* Create initial list. */
 		this->signs.ForceRebuild();
 		this->signs.ForceResort();
-		this->BuildSignsList();
+		this->BuildSortSignList();
-		this->SortSignsList();
-		this->vscroll->SetCount(this->signs.Length());
 	}
 
 	/**
@@ -214,6 +212,7 @@ struct SignListWindow : QueryStringBaseWindow, SignList {
 
 	virtual void OnPaint()
 	{
+		if (this->signs.NeedRebuild()) this->BuildSortSignList();
 		this->DrawWidgets();
 		if (!this->IsShaded()) this->DrawEditBox(SLW_FILTER_TEXT);
 	}
@@ -352,23 +351,38 @@ struct SignListWindow : QueryStringBaseWindow, SignList {
 		this->HandleEditBox(SLW_FILTER_TEXT);
 	}
 
+	void BuildSortSignList()
+	{
+		if (this->signs.NeedRebuild()) {
+			this->BuildSignsList();
+			this->vscroll->SetCount(this->signs.Length());
+			this->SetWidgetDirty(SLW_CAPTION);
+		}
+		this->SortSignsList();
+	}
 
-	virtual void OnInvalidateData(int data)
+	virtual void OnHundredthTick()
+	{
+		this->BuildSortSignList();
+		this->SetDirty();
+	}
+
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		/* When there is a filter string, we always need to rebuild the list even if
 		 * the amount of signs in total is unchanged, as the subset of signs that is
-		 * accepted by the filter might has changed.
+		 * accepted by the filter might has changed. */
-		 */
 		if (data == 0 || !StrEmpty(this->filter_string)) { // New or deleted sign, or there is a filter string
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->signs.ForceRebuild();
-			this->BuildSignsList();
-			this->SetWidgetDirty(SLW_CAPTION);
-			this->vscroll->SetCount(this->signs.Length());
 		} else { // Change of sign contents while there is no filter string
 			this->signs.ForceResort();
 		}
-
-		this->SortSignsList();
 	}
 
 	static Hotkey<SignListWindow> signlist_hotkeys[];

src/smallmap_gui.cpp

@@ -1423,12 +1423,15 @@ public:
 	}
 
 	/**
-	 * Notifications for the smallmap window.
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
 	 * - data = 0: Displayed industries at the industry chain window have changed.
 	 * - data = 1: Companies have changed.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
 	 */
-	virtual void OnInvalidateData(int data)
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		switch (data) {
 			case 1:
 				/* The owner legend has already been rebuilt. */

src/station_gui.cpp

@@ -687,9 +687,15 @@ public:
 		this->vscroll->SetCapacityFromWidget(this, SLW_LIST, WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->stations.ForceRebuild();
 		} else {
 			this->stations.ForceResort();
@@ -1448,8 +1454,14 @@ struct SelectStationWindow : Window {
 		this->vscroll->SetCapacityFromWidget(this, JSW_PANEL, WD_FRAMERECT_TOP + WD_FRAMERECT_BOTTOM);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		FindStationsNearby<T>(this->area, true);
 		this->vscroll->SetCount(_stations_nearby_list.Length() + 1);
 		this->SetDirty();

src/statusbar_gui.cpp

@@ -183,8 +183,14 @@ struct StatusBarWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		switch (data) {
 			default: NOT_REACHED();
 			case SBI_SAVELOAD_START:  this->saving = true;  break;

src/subsidy_gui.cpp

@@ -215,8 +215,14 @@ struct SubsidyListWindow : Window {
 		this->vscroll->SetCapacityFromWidget(this, SLW_PANEL);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->vscroll->SetCount(this->CountLines());
 	}
 };

src/timetable_gui.cpp

@@ -243,10 +243,15 @@ struct TimetableWindow : Window {
 		return (sel < v->GetNumOrders() * 2 && sel >= 0) ? sel : INVALID_ORDER;
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		switch (data) {
-			case 0:
+			case -666:
 				/* Autoreplace replaced the vehicle */
 				this->vehicle = Vehicle::Get(this->window_number);
 				break;
@@ -260,11 +265,14 @@ struct TimetableWindow : Window {
 				break;
 
 			case -2:
+				if (!gui_scope) break;
 				this->UpdateSelectionStates();
 				this->ReInit();
 				break;
 
 			default: {
+				if (gui_scope) break; // only do this once; from command scope
+
 				/* Moving an order. If one of these is INVALID_VEH_ORDER_ID, then
 				 * the order is being created / removed */
 				if (this->sel_index == -1) break;

src/toolbar_gui.cpp

@@ -1482,8 +1482,14 @@ struct MainToolbarWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (FindWindowById(WC_MAIN_WINDOW, 0) != NULL) HandleZoomMessage(this, FindWindowById(WC_MAIN_WINDOW, 0)->viewport, TBN_ZOOMIN, TBN_ZOOMOUT);
 	}
 
@@ -1792,8 +1798,14 @@ struct ScenarioEditorToolbarWindow : Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		if (FindWindowById(WC_MAIN_WINDOW, 0) != NULL) HandleZoomMessage(this, FindWindowById(WC_MAIN_WINDOW, 0)->viewport, TBSE_ZOOMIN, TBSE_ZOOMOUT);
 	}
 

src/town_gui.cpp

@@ -523,8 +523,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Called when setting station noise or required cargos have changed, in order to resize the window */
 		this->SetDirty(); // refresh display for current size. This will allow to avoid glitches when downgrading
 		this->ResizeWindowAsNeeded();
@@ -846,6 +852,12 @@ public:
 		}
 	}
 
+	virtual void OnPaint()
+	{
+		if (this->towns.NeedRebuild()) this->BuildSortTownList();
+		this->DrawWidgets();
+	}
+
 	virtual void OnHundredthTick()
 	{
 		this->BuildSortTownList();
@@ -857,14 +869,19 @@ public:
 		this->vscroll->SetCapacityFromWidget(this, TDW_CENTERTOWN);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		if (data == 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->towns.ForceRebuild();
 		} else {
 			this->towns.ForceResort();
 		}
-		this->BuildSortTownList();
 	}
 };
 
@@ -1157,8 +1174,14 @@ public:
 		this->UpdateButtons(false);
 	}
 
-	virtual void OnInvalidateData(int)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->UpdateButtons(true);
 	}
 };

src/train_cmd.cpp

@@ -264,7 +264,7 @@ void Train::ConsistChanged(bool same_length)
 	if (this->IsFrontEngine()) {
 		this->UpdateAcceleration();
 		SetWindowDirty(WC_VEHICLE_DETAILS, this->index);
-		InvalidateWindowData(WC_VEHICLE_REFIT, this->index); // Important, do not invalidate immediately. The refit window tests commands.
+		InvalidateWindowData(WC_VEHICLE_REFIT, this->index);
 	}
 }
 
@@ -1092,7 +1092,7 @@ static void NormaliseTrainHead(Train *head)
 	if (!head->IsFrontEngine()) return;
 
 	/* Update the refit button and window */
-	InvalidateWindowData(WC_VEHICLE_REFIT, head->index); // Important, do not invalidate immediately. The refit window tests commands.
+	InvalidateWindowData(WC_VEHICLE_REFIT, head->index);
 	SetWindowWidgetDirty(WC_VEHICLE_VIEW, head->index, VVW_WIDGET_REFIT_VEH);
 
 	/* If we don't have a unit number yet, set one. */

src/transparency_gui.cpp

@@ -125,8 +125,14 @@ public:
 		return pt;
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		for (uint i = TTW_WIDGET_BEGIN; i < TTW_WIDGET_END; i++) {
 			this->SetWidgetLoweredState(i, IsTransparencySet((TransparencyOption)(i - TTW_WIDGET_BEGIN)));
 		}

src/tree_gui.cpp

@@ -144,8 +144,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		this->base  = _tree_base_by_landscape[_settings_game.game_creation.landscape];
 		this->count = _tree_count_by_landscape[_settings_game.game_creation.landscape];
 	}

src/vehicle.cpp

@@ -2270,7 +2270,7 @@ void Vehicle::RemoveFromShared()
 	} else if (were_first) {
 		/* If we were the first one, update to the new first one.
 		 * Note: FirstShared() is already the new first */
-		InvalidateWindowData(GetWindowClassForVehicleType(this->type), vli.Pack(), this->FirstShared()->index | (1U << 31), true);
+		InvalidateWindowData(GetWindowClassForVehicleType(this->type), vli.Pack(), this->FirstShared()->index | (1U << 31));
 	}
 
 	this->next_shared     = NULL;

src/vehicle_gui.cpp

@@ -683,9 +683,15 @@ struct RefitWindow : public Window {
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
 		switch (data) {
+			case -666: // Autoreplace replaced the vehicle; selected_vehicle became invalid.
 			case 0: { // The consist has changed; rebuild the entire list.
 				/* Clear the selection. */
 				Vehicle *v = Vehicle::Get(this->window_number);
@@ -695,6 +701,7 @@ struct RefitWindow : public Window {
 			}
 
 			case 2: { // The vehicle selection has changed; rebuild the entire list.
+				if (!gui_scope) break;
 				this->BuildRefitList();
 
 				/* The vehicle width has changed too. */
@@ -720,6 +727,7 @@ struct RefitWindow : public Window {
 			}
 
 			case 1: // A new cargo has been selected.
+				if (!gui_scope) break;
 				this->cargo = GetRefitOption();
 				break;
 		}
@@ -1120,8 +1128,8 @@ static inline void ChangeVehicleWindow(WindowClass window_class, VehicleID from_
 			_thd.window_number = to_index;
 		}
 
-		/* Notify the window immediately, without scheduling. */
+		/* Notify the window. */
-		w->InvalidateData();
+		w->InvalidateData(-666, false);
 	}
 }
 
@@ -1594,9 +1602,15 @@ public:
 		this->GetWidget<NWidgetCore>(VLW_WIDGET_LIST)->widget_data = (this->vscroll->GetCapacity() << MAT_ROW_START) + (1 << MAT_COL_START);
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
-		if (HasBit(data, 31) && this->vli.type == VL_SHARED_ORDERS) {
+		if (!gui_scope && HasBit(data, 31) && this->vli.type == VL_SHARED_ORDERS) {
+			/* Needs to be done in command-scope, so everything stays valid */
 			this->vli.index = GB(data, 0, 20);
 			this->window_number = this->vli.Pack();
 			this->vehicles.ForceRebuild();
@@ -1604,6 +1618,7 @@ public:
 		}
 
 		if (data == 0) {
+			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->vehicles.ForceRebuild();
 		} else {
 			this->vehicles.ForceResort();
@@ -1778,8 +1793,19 @@ struct VehicleDetailsWindow : Window {
 		this->tab = TDW_TAB_CARGO;
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (data == -666) {
+			/* Autoreplace replaced the vehicle.
+			 * Nothing to do for this window. */
+			return;
+		}
+		if (!gui_scope) return;
 		const Vehicle *v = Vehicle::Get(this->window_number);
 		if (v->type == VEH_ROAD) {
 			const NWidgetBase *nwid_info = this->GetWidget<NWidgetBase>(VLD_WIDGET_MIDDLE_DETAILS);
@@ -2581,6 +2607,20 @@ public:
 		}
 	}
 
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
+	{
+		if (data == -666) {
+			/* Autoreplace replaced the vehicle.
+			 * Nothing to do for this window. */
+			return;
+		}
+	}
+
 	virtual bool IsNewGRFInspectable() const
 	{
 		return ::IsNewGRFInspectable(GetGrfSpecFeature(Vehicle::Get(this->window_number)->type), this->window_number);

src/viewport_gui.cpp

@@ -148,8 +148,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data = 0)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* Only handle zoom message if intended for us (msg ZOOM_IN/ZOOM_OUT) */
 		HandleZoomMessage(this, this->viewport, EVW_ZOOMIN, EVW_ZOOMOUT);
 	}

src/waypoint_gui.cpp

@@ -114,8 +114,14 @@ public:
 		}
 	}
 
-	virtual void OnInvalidateData(int data)
+	/**
+	 * Some data on this window has become invalid.
+	 * @param data Information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
+	 */
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (!gui_scope) return;
 		/* You can only change your own waypoints */
 		this->SetWidgetDisabledState(WAYPVW_RENAME, !this->wp->IsInUse() || (this->wp->owner != _local_company && this->wp->owner != OWNER_NONE));
 		/* Disable the widget for waypoints with no use */

src/window.cpp

@@ -2403,6 +2403,11 @@ void InputLoop()
 void UpdateWindows()
 {
 	Window *w;
+
+	FOR_ALL_WINDOWS_FROM_FRONT(w) {
+		w->ProcessScheduledInvalidations();
+	}
+
 	static int we4_timer = 0;
 	int t = we4_timer + 1;
 
@@ -2420,7 +2425,6 @@ void UpdateWindows()
 
 			if (!(w->flags4 & WF_WHITE_BORDER_MASK)) w->SetDirty();
 		}
-		w->ProcessScheduledInvalidations();
 	}
 
 	DrawDirtyBlocks();
@@ -2477,46 +2481,55 @@ void SetWindowClassesDirty(WindowClass cls)
 
 /**
  * Mark window data of the window of a given class and specific window number as invalid (in need of re-computing)
- * Note that by default the invalidation is not executed immediately but is scheduled till the next redraw.
+ *
+ * Note that by default the invalidation is not considered to be called from GUI scope.
+ * That means only a part of invalidation is executed immediately. The rest is scheduled for the next redraw.
  * The asynchronous execution is important to prevent GUI code being executed from command scope.
+ * When not in GUI-scope:
+ *  - OnInvalidateData() may not do test-runs on commands, as they might affect the execution of
+ *    the command which triggered the invalidation. (town rating and such)
+ *  - OnInvalidateData() may not rely on _current_company == _local_company.
+ *    This implies that no NewGRF callbacks may be run.
+ *
+ * However, when invalidations are scheduled, then multiple calls may be scheduled before execution starts. Earlier scheduled
+ * invalidations may be called with invalidation-data, which is already invalid at the point of execution.
+ * That means some stuff requires to be executed immediately in command scope, while not everything may be executed in command
+ * scope. While GUI-scope calls have no restrictions on what they may do, they cannot assume the game to still be in the state
+ * when the invalidation was scheduled; passed IDs may have got invalid in the mean time.
+ *
+ * Finally, note that invalidations triggered from commands or the game loop result in OnInvalidateData() being called twice.
+ * Once in command-scope, once in GUI-scope. So make sure to not process differential-changes twice.
+ *
  * @param cls Window class
  * @param number Window number within the class
  * @param data The data to invalidate with
- * @param immediately If true then do not schedule the event, but execute immediately.
+ * @param gui_scope Whether the call is done from GUI scope
  */
-void InvalidateWindowData(WindowClass cls, WindowNumber number, int data, bool immediately)
+void InvalidateWindowData(WindowClass cls, WindowNumber number, int data, bool gui_scope)
 {
 	Window *w;
 	FOR_ALL_WINDOWS_FROM_BACK(w) {
 		if (w->window_class == cls && w->window_number == number) {
-			if (immediately) {
+			w->InvalidateData(data, gui_scope);
-				w->InvalidateData(data);
-			} else {
-				w->ScheduleInvalidateData(data);
-			}
 		}
 	}
 }
 
 /**
  * Mark window data of all windows of a given class as invalid (in need of re-computing)
- * Note that by default the invalidation is not executed immediately but is scheduled till the next redraw.
+ * Note that by default the invalidation is not considered to be called from GUI scope.
- * The asynchronous execution is important to prevent GUI code being executed from command scope.
+ * See InvalidateWindowData() for details on GUI-scope vs. command-scope.
  * @param cls Window class
  * @param data The data to invalidate with
- * @param immediately If true then do not schedule the event, but execute immediately.
+ * @param gui_scope Whether the call is done from GUI scope
  */
-void InvalidateWindowClassesData(WindowClass cls, int data, bool immediately)
+void InvalidateWindowClassesData(WindowClass cls, int data, bool gui_scope)
 {
 	Window *w;
 
 	FOR_ALL_WINDOWS_FROM_BACK(w) {
 		if (w->window_class == cls) {
-			if (immediately) {
+			w->InvalidateData(data, gui_scope);
-				w->InvalidateData(data);
-			} else {
-				w->ScheduleInvalidateData(data);
-			}
 		}
 	}
 }

src/window_func.h

@@ -34,8 +34,8 @@ void ResetWindowSystem();
 void SetupColoursAndInitialWindow();
 void InputLoop();
 
-void InvalidateWindowData(WindowClass cls, WindowNumber number, int data = 0, bool immediately = false);
+void InvalidateWindowData(WindowClass cls, WindowNumber number, int data = 0, bool gui_scope = false);
-void InvalidateWindowClassesData(WindowClass cls, int data = 0, bool immediately = false);
+void InvalidateWindowClassesData(WindowClass cls, int data = 0, bool gui_scope = false);
 
 void DeleteNonVitalWindows();
 void DeleteAllNonVitalWindows();

src/window_gui.h

@@ -434,22 +434,16 @@ public:
 	/**
 	 * Mark this window's data as invalid (in need of re-computing)
 	 * @param data The data to invalidate with
+	 * @param gui_scope Whether the funtion is called from GUI scope.
 	 */
-	void InvalidateData(int data = 0)
+	void InvalidateData(int data = 0, bool gui_scope = true)
 	{
 		this->SetDirty();
-		this->OnInvalidateData(data);
+		if (!gui_scope) {
-	}
+			/* Schedule GUI-scope invalidation for next redraw. */
-
+			*this->scheduled_invalidation_data.Append() = data;
-	/**
+		}
-	 * Schedule a invalidation call for next redraw.
+		this->OnInvalidateData(data, gui_scope);
-	 * Important for asynchronous invalidation from commands.
-	 * @param data The data to invalidate with
-	 */
-	void ScheduleInvalidateData(int data = 0)
-	{
-		this->SetDirty();
-		*this->scheduled_invalidation_data.Append() = data;
 	}
 
 	/**
@@ -458,7 +452,7 @@ public:
 	void ProcessScheduledInvalidations()
 	{
 		for (int *data = this->scheduled_invalidation_data.Begin(); this->window_class != WC_INVALID && data != this->scheduled_invalidation_data.End(); data++) {
-			this->OnInvalidateData(*data);
+			this->OnInvalidateData(*data, true);
 		}
 		this->scheduled_invalidation_data.Clear();
 	}
@@ -651,9 +645,9 @@ public:
 	/**
 	 * Some data on this window has become invalid.
 	 * @param data information about the changed data.
+	 * @param gui_scope Whether the call is done from GUI scope. You may not do everything when not in GUI scope. See #InvalidateWindowData() for details.
 	 */
-	virtual void OnInvalidateData(int data = 0) {}
+	virtual void OnInvalidateData(int data = 0, bool gui_scope = true) {}
-
 
 	/**
 	 * The user clicked some place on the map when a tile highlight mode