diff --git a/src/autoreplace_gui.cpp b/src/autoreplace_gui.cpp
index 69fc99e44b..fede79ef85 100644
--- a/src/autoreplace_gui.cpp
+++ b/src/autoreplace_gui.cpp
@@ -217,7 +217,7 @@ class ReplaceVehicleWindow : public Window {
 		if (this->engines[0].NeedRebuild()) {
 			/* We need to rebuild the left engines list */
 			this->GenerateReplaceVehList(true);
-			this->vscroll[0]->SetCount((uint)this->engines[0].size());
+			this->vscroll[0]->SetCount(this->engines[0].size());
 			if (this->reset_sel_engine && this->sel_engine[0] == INVALID_ENGINE && this->engines[0].size() != 0) {
 				this->sel_engine[0] = this->engines[0][0].engine_id;
 			}
@@ -237,7 +237,7 @@ class ReplaceVehicleWindow : public Window {
 				}
 				/* Regenerate the list on the right. Note: This resets sel_engine[1] to INVALID_ENGINE, if it is no longer available. */
 				this->GenerateReplaceVehList(false);
-				this->vscroll[1]->SetCount((uint)this->engines[1].size());
+				this->vscroll[1]->SetCount(this->engines[1].size());
 				if (this->reset_sel_engine && this->sel_engine[1] != INVALID_ENGINE) {
 					int position = 0;
 					for (const auto &item : this->engines[1]) {
diff --git a/src/bridge_gui.cpp b/src/bridge_gui.cpp
index 0ed9ea78cc..f2e20c7b21 100644
--- a/src/bridge_gui.cpp
+++ b/src/bridge_gui.cpp
@@ -167,7 +167,7 @@ public:
 		this->bridges->NeedResort();
 		this->SortBridgeList();
 
-		this->vscroll->SetCount((uint)bl->size());
+		this->vscroll->SetCount(bl->size());
 	}
 
 	~BuildBridgeWindow()
diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
index 84ff30fb29..0e9a7d727a 100644
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -1787,7 +1787,7 @@ struct BuildVehicleWindow : Window {
 	void OnPaint() override
 	{
 		this->GenerateBuildList();
-		this->vscroll->SetCount((uint)this->eng_list.size());
+		this->vscroll->SetCount(this->eng_list.size());
 
 		this->SetWidgetsDisabledState(this->sel_engine == INVALID_ENGINE, WID_BV_SHOW_HIDE, WID_BV_BUILD, WIDGET_LIST_END);
 
diff --git a/src/depot_gui.cpp b/src/depot_gui.cpp
index fa8aca26ec..e05682c5a5 100644
--- a/src/depot_gui.cpp
+++ b/src/depot_gui.cpp
@@ -735,7 +735,7 @@ struct DepotWindow : Window {
 				max_width = std::max(max_width, width);
 			}
 			/* Always have 1 empty row, so people can change the setting of the train */
-			this->vscroll->SetCount((uint)this->vehicle_list.size() + (uint)this->wagon_list.size() + 1);
+			this->vscroll->SetCount(this->vehicle_list.size() + this->wagon_list.size() + 1);
 			/* Always make it longer than the longest train, so you can attach vehicles at the end, and also see the next vertical tile separator line */
 			this->hscroll->SetCount(max_width + ScaleSpriteTrad(2 * VEHICLEINFO_FULL_VEHICLE_WIDTH + 1));
 		} else {
diff --git a/src/fios_gui.cpp b/src/fios_gui.cpp
index bfe14e486d..07e55384d7 100644
--- a/src/fios_gui.cpp
+++ b/src/fios_gui.cpp
@@ -821,7 +821,7 @@ public:
 
 				_fios_path_changed = true;
 				this->fios_items.BuildFileList(this->abstract_filetype, this->fop);
-				this->vscroll->SetCount((uint)this->fios_items.size());
+				this->vscroll->SetCount(this->fios_items.size());
 				this->selected = nullptr;
 				_load_check_data.Clear();
 
diff --git a/src/game/game_gui.cpp b/src/game/game_gui.cpp
index 0885f38db6..5ce1c3d7eb 100644
--- a/src/game/game_gui.cpp
+++ b/src/game/game_gui.cpp
@@ -127,7 +127,7 @@ struct GSConfigWindow : public Window {
 			}
 		}
 
-		this->vscroll->SetCount((int)this->visible_settings.size());
+		this->vscroll->SetCount(this->visible_settings.size());
 	}
 
 	void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp
index 47e596177a..57d6cc9192 100644
--- a/src/graph_gui.cpp
+++ b/src/graph_gui.cpp
@@ -892,7 +892,7 @@ struct PaymentRatesGraphWindow : BaseGraphWindow {
 
 		this->CreateNestedTree();
 		this->vscroll = this->GetScrollbar(WID_CPR_MATRIX_SCROLLBAR);
-		this->vscroll->SetCount(static_cast<int>(_sorted_standard_cargo_specs.size()));
+		this->vscroll->SetCount(_sorted_standard_cargo_specs.size());
 
 		/* Initialise the dataset */
 		this->UpdatePaymentRates();
diff --git a/src/group_gui.cpp b/src/group_gui.cpp
index 704c41ec91..f6521c34a9 100644
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -364,7 +364,7 @@ public:
 		this->groups.ForceRebuild();
 		this->groups.NeedResort();
 		this->BuildGroupList(vli.company);
-		this->group_sb->SetCount((uint)this->groups.size());
+		this->group_sb->SetCount(this->groups.size());
 
 		this->GetWidget<NWidgetCore>(WID_GL_CAPTION)->widget_data = STR_VEHICLE_LIST_TRAIN_CAPTION + this->vli.vtype;
 		this->GetWidget<NWidgetCore>(WID_GL_LIST_VEHICLE)->tool_tip = STR_VEHICLE_LIST_TRAIN_LIST_TOOLTIP + this->vli.vtype;
@@ -506,8 +506,8 @@ public:
 
 		this->BuildGroupList(this->owner);
 
-		this->group_sb->SetCount(static_cast<int>(this->groups.size()));
-		this->vscroll->SetCount(static_cast<int>(this->vehgroups.size()));
+		this->group_sb->SetCount(this->groups.size());
+		this->vscroll->SetCount(this->vehgroups.size());
 
 		/* The drop down menu is out, *but* it may not be used, retract it. */
 		if (this->vehicles.size() == 0 && this->IsWidgetLowered(WID_GL_MANAGE_VEHICLES_DROPDOWN)) {
@@ -1087,7 +1087,7 @@ public:
 				}
 				this->groups.ForceRebuild();
 				this->BuildGroupList(this->owner);
-				this->group_sb->SetCount((uint)this->groups.size());
+				this->group_sb->SetCount(this->groups.size());
 				id_g = find_index(this->groups, g);
 			}
 			this->group_sb->ScrollTowards(id_g);
diff --git a/src/industry_gui.cpp b/src/industry_gui.cpp
index 1d85abbe8e..0b419637ba 100644
--- a/src/industry_gui.cpp
+++ b/src/industry_gui.cpp
@@ -325,7 +325,7 @@ class BuildIndustryWindow : public Window {
 
 		this->UpdateAvailability();
 
-		this->vscroll->SetCount((int)this->list.size());
+		this->vscroll->SetCount(this->list.size());
 	}
 
 	/** Update status of the fund and display-chain widgets. */
@@ -1419,7 +1419,7 @@ protected:
 		IndustryDirectoryWindow::produced_cargo_filter = this->cargo_filter[this->produced_cargo_filter_criteria];
 		this->industries.Sort();
 
-		this->vscroll->SetCount((uint)this->industries.size()); // Update scrollbar as well.
+		this->vscroll->SetCount(this->industries.size()); // Update scrollbar as well.
 
 		this->SetDirty();
 	}
diff --git a/src/network/network_content_gui.cpp b/src/network/network_content_gui.cpp
index 7d53329069..18b5470051 100644
--- a/src/network/network_content_gui.cpp
+++ b/src/network/network_content_gui.cpp
@@ -423,7 +423,7 @@ class NetworkContentListWindow : public Window, ContentCallback {
 		this->content.RebuildDone();
 		this->SortContentList();
 
-		this->vscroll->SetCount((int)this->content.size()); // Update the scrollbar
+		this->vscroll->SetCount(this->content.size()); // Update the scrollbar
 		this->ScrollToSelected();
 	}
 
diff --git a/src/network/network_gui.cpp b/src/network/network_gui.cpp
index 63f2284247..72d3d7d94b 100644
--- a/src/network/network_gui.cpp
+++ b/src/network/network_gui.cpp
@@ -279,7 +279,7 @@ protected:
 
 		this->servers.shrink_to_fit();
 		this->servers.RebuildDone();
-		this->vscroll->SetCount((int)this->servers.size());
+		this->vscroll->SetCount(this->servers.size());
 
 		/* Sort the list of network games as requested. */
 		this->servers.Sort();
diff --git a/src/newgrf_debug_gui.cpp b/src/newgrf_debug_gui.cpp
index ff927c2952..026768f15e 100644
--- a/src/newgrf_debug_gui.cpp
+++ b/src/newgrf_debug_gui.cpp
@@ -1055,7 +1055,7 @@ struct SpriteAlignerWindow : Window {
 		if (data == 1) {
 			/* Sprite picker finished */
 			this->RaiseWidget(WID_SA_PICKER);
-			this->vscroll->SetCount((uint)_newgrf_debug_sprite_picker.sprites.size());
+			this->vscroll->SetCount(_newgrf_debug_sprite_picker.sprites.size());
 		}
 	}
 
diff --git a/src/newgrf_gui.cpp b/src/newgrf_gui.cpp
index 663de441c2..a4323dc98f 100644
--- a/src/newgrf_gui.cpp
+++ b/src/newgrf_gui.cpp
@@ -1490,7 +1490,7 @@ private:
 			}
 		}
 
-		this->vscroll2->SetCount((uint)this->avails.size()); // Update the scrollbar
+		this->vscroll2->SetCount(this->avails.size()); // Update the scrollbar
 	}
 
 	/**
@@ -2068,7 +2068,7 @@ struct SavePresetWindow : public Window {
 		this->vscroll = this->GetScrollbar(WID_SVP_SCROLLBAR);
 		this->FinishInitNested(0);
 
-		this->vscroll->SetCount((uint)this->presets.size());
+		this->vscroll->SetCount(this->presets.size());
 		this->SetFocusedWidget(WID_SVP_EDITBOX);
 		if (initial_text != nullptr) this->presetname_editbox.text.Assign(initial_text);
 	}
diff --git a/src/object_gui.cpp b/src/object_gui.cpp
index 414d930e5d..a598853e5b 100644
--- a/src/object_gui.cpp
+++ b/src/object_gui.cpp
@@ -125,7 +125,7 @@ public:
 
 		ResetObjectToPlace();
 
-		this->vscroll->SetCount((int)this->object_classes.size());
+		this->vscroll->SetCount(this->object_classes.size());
 
 		EnsureSelectedObjectClassIsVisible();
 
@@ -166,7 +166,7 @@ public:
 		this->object_classes.RebuildDone();
 		this->object_classes.Sort();
 
-		this->vscroll->SetCount((uint)this->object_classes.size());
+		this->vscroll->SetCount(this->object_classes.size());
 	}
 
 	/**
diff --git a/src/rail_gui.cpp b/src/rail_gui.cpp
index 71f7bd5a8a..54e7443825 100644
--- a/src/rail_gui.cpp
+++ b/src/rail_gui.cpp
@@ -929,7 +929,7 @@ private:
 			if (station_class == _railstation.station_class) break;
 			pos++;
 		}
-		this->vscroll->SetCount((int)this->station_classes.size());
+		this->vscroll->SetCount(this->station_classes.size());
 		this->vscroll->ScrollTowards(pos);
 	}
 
@@ -1075,7 +1075,7 @@ public:
 			this->station_classes.RebuildDone();
 			this->station_classes.Sort();
 
-			this->vscroll->SetCount((uint)this->station_classes.size());
+			this->vscroll->SetCount(this->station_classes.size());
 		}
 	}
 
diff --git a/src/road_gui.cpp b/src/road_gui.cpp
index 2dc7ec39f9..4731f2e606 100644
--- a/src/road_gui.cpp
+++ b/src/road_gui.cpp
@@ -1135,7 +1135,7 @@ private:
 			if (rs_class == _roadstop_gui_settings.roadstop_class) break;
 			pos++;
 		}
-		this->vscrollList->SetCount((int)this->roadstop_classes.size());
+		this->vscrollList->SetCount(this->roadstop_classes.size());
 		this->vscrollList->ScrollTowards(pos);
 	}
 
@@ -1281,7 +1281,7 @@ public:
 			this->roadstop_classes.RebuildDone();
 			this->roadstop_classes.Sort();
 
-			this->vscrollList->SetCount((uint)this->roadstop_classes.size());
+			this->vscrollList->SetCount(this->roadstop_classes.size());
 		}
 	}
 
diff --git a/src/script/script_gui.cpp b/src/script/script_gui.cpp
index e77c1c7ede..673747f2cd 100644
--- a/src/script/script_gui.cpp
+++ b/src/script/script_gui.cpp
@@ -77,7 +77,7 @@ struct ScriptListWindow : public Window {
 		this->vscroll = this->GetScrollbar(WID_SCRL_SCROLLBAR);
 		this->FinishInitNested(); // Initializes 'this->line_height' as side effect.
 
-		this->vscroll->SetCount((int)this->info_list->size() + 1);
+		this->vscroll->SetCount(this->info_list->size() + 1);
 
 		/* Try if we can find the currently selected AI */
 		this->selected = -1;
@@ -231,7 +231,7 @@ struct ScriptListWindow : public Window {
 
 		if (!gui_scope) return;
 
-		this->vscroll->SetCount((int)this->info_list->size() + 1);
+		this->vscroll->SetCount(this->info_list->size() + 1);
 
 		/* selected goes from -1 .. length of ai list - 1. */
 		this->selected = std::min(this->selected, this->vscroll->GetCount() - 2);
@@ -332,7 +332,7 @@ struct ScriptSettingsWindow : public Window {
 			}
 		}
 
-		this->vscroll->SetCount((int)this->visible_settings.size());
+		this->vscroll->SetCount(this->visible_settings.size());
 	}
 
 	void SetStringParameters(int widget) const override
@@ -1070,7 +1070,7 @@ struct ScriptDebugWindow : public Window {
 
 		this->SelectValidDebugCompany();
 
-		this->vscroll->SetCount(script_debug_company != INVALID_COMPANY ? (int)this->GetLogData().size() : 0);
+		this->vscroll->SetCount(script_debug_company != INVALID_COMPANY ? this->GetLogData().size() : 0);
 
 		/* Update company buttons */
 		for (CompanyID i = COMPANY_FIRST; i < MAX_COMPANIES; i++) {
diff --git a/src/signs_gui.cpp b/src/signs_gui.cpp
index 925956b93f..070ee6261a 100644
--- a/src/signs_gui.cpp
+++ b/src/signs_gui.cpp
@@ -308,7 +308,7 @@ struct SignListWindow : Window, SignList {
 	{
 		if (this->signs.NeedRebuild()) {
 			this->BuildSignsList();
-			this->vscroll->SetCount((uint)this->signs.size());
+			this->vscroll->SetCount(this->signs.size());
 			this->SetWidgetDirty(WID_SIL_CAPTION);
 		}
 		this->SortSignsList();
diff --git a/src/station_gui.cpp b/src/station_gui.cpp
index 052b5f2783..e206aec033 100644
--- a/src/station_gui.cpp
+++ b/src/station_gui.cpp
@@ -252,7 +252,7 @@ protected:
 		this->stations.shrink_to_fit();
 		this->stations.RebuildDone();
 
-		this->vscroll->SetCount((uint)this->stations.size()); // Update the scrollbar
+		this->vscroll->SetCount(this->stations.size()); // Update the scrollbar
 	}
 
 	/** Sort stations by their name */
@@ -2345,7 +2345,7 @@ struct SelectStationWindow : Window {
 	{
 		if (!gui_scope) return;
 		FindStationsNearby<T>(this->area, true);
-		this->vscroll->SetCount((uint)_stations_nearby_list.size() + 1);
+		this->vscroll->SetCount(_stations_nearby_list.size() + 1);
 		this->SetDirty();
 	}
 
diff --git a/src/town_gui.cpp b/src/town_gui.cpp
index 54142d1207..c42b92f58c 100644
--- a/src/town_gui.cpp
+++ b/src/town_gui.cpp
@@ -736,7 +736,7 @@ private:
 
 			this->towns.shrink_to_fit();
 			this->towns.RebuildDone();
-			this->vscroll->SetCount((uint)this->towns.size()); // Update scrollbar as well.
+			this->vscroll->SetCount(this->towns.size()); // Update scrollbar as well.
 		}
 		/* Always sort the towns. */
 		this->towns.Sort();
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 80c9e7218b..50c5267ea9 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -224,7 +224,7 @@ void BaseVehicleListWindow::BuildVehicleList()
 	}
 
 	this->vehgroups.RebuildDone();
-	this->vscroll->SetCount(static_cast<int>(this->vehgroups.size()));
+	this->vscroll->SetCount(this->vehgroups.size());
 }
 
 
diff --git a/src/widget_type.h b/src/widget_type.h
index 7643537aa5..0e8f940c60 100644
--- a/src/widget_type.h
+++ b/src/widget_type.h
@@ -704,10 +704,11 @@ public:
 	 * Set the distance to scroll when using the buttons or the wheel.
 	 * @param stepsize Scrolling speed.
 	 */
-	void SetStepSize(uint16 stepsize)
+	void SetStepSize(size_t stepsize)
 	{
 		assert(stepsize > 0);
-		this->stepsize = stepsize;
+
+		this->stepsize = ClampTo<uint16_t>(stepsize);
 	}
 
 	/**
@@ -715,12 +716,11 @@ public:
 	 * @param num the number of elements in the list
 	 * @note updates the position if needed
 	 */
-	void SetCount(int num)
+	void SetCount(size_t num)
 	{
-		assert(num >= 0);
 		assert(num <= MAX_UVALUE(uint16));
 
-		this->count = num;
+		this->count = ClampTo<uint16_t>(num);
 		num -= this->cap;
 		if (num < 0) num = 0;
 		if (num < this->pos) this->pos = num;
@@ -731,12 +731,11 @@ public:
 	 * @param capacity the new capacity
 	 * @note updates the position if needed
 	 */
-	void SetCapacity(int capacity)
+	void SetCapacity(size_t capacity)
 	{
-		assert(capacity > 0);
 		assert(capacity <= MAX_UVALUE(uint16));
 
-		this->cap = capacity;
+		this->cap = ClampTo<uint16_t>(capacity);
 		if (this->cap + this->pos > this->count) this->pos = std::max(0, this->count - this->cap);
 	}
 
diff --git a/src/widgets/dropdown.cpp b/src/widgets/dropdown.cpp
index 1c7a7492e7..a9eb238453 100644
--- a/src/widgets/dropdown.cpp
+++ b/src/widgets/dropdown.cpp
@@ -172,8 +172,8 @@ struct DropdownWindow : Window {
 		}
 
 		/* Capacity is the average number of items visible */
-		this->vscroll->SetCapacity(size.height * (uint16)this->list.size() / list_height);
-		this->vscroll->SetCount((uint16)this->list.size());
+		this->vscroll->SetCapacity(size.height * this->list.size() / list_height);
+		this->vscroll->SetCount(this->list.size());
 
 		this->parent_wnd_class = parent->window_class;
 		this->parent_wnd_num   = parent->window_number;