diff --git a/src/textbuf.cpp b/src/textbuf.cpp
index c7071565ab..58f931f8a5 100644
--- a/src/textbuf.cpp
+++ b/src/textbuf.cpp
@@ -362,7 +362,7 @@ bool Textbuf::HandleCaret()
 	return false;
 }
 
-HandleKeyPressResult Textbuf::HandleKeyPress(uint16 key, uint16 keycode)
+HandleKeyPressResult Textbuf::HandleKeyPress(WChar key, uint16 keycode)
 {
 	bool edited = false;
 
diff --git a/src/textbuf_type.h b/src/textbuf_type.h
index 4d1a926fbe..5976159909 100644
--- a/src/textbuf_type.h
+++ b/src/textbuf_type.h
@@ -56,7 +56,7 @@ struct Textbuf {
 	bool DeleteChar(uint16 keycode);
 	bool MovePos(uint16 keycode);
 
-	HandleKeyPressResult HandleKeyPress(uint16 key, uint16 keycode);
+	HandleKeyPressResult HandleKeyPress(WChar key, uint16 keycode);
 
 	bool HandleCaret();
 	void UpdateSize();
diff --git a/src/window.cpp b/src/window.cpp
index d3d9baadd8..bf51fd7ad1 100644
--- a/src/window.cpp
+++ b/src/window.cpp
@@ -2378,7 +2378,7 @@ static bool MaybeBringWindowToFront(Window *w)
  * @return #ES_HANDLED if the key press has been handled and no other
  *         window should receive the event.
  */
-EventState Window::HandleEditBoxKey(int wid, uint16 key, uint16 keycode)
+EventState Window::HandleEditBoxKey(int wid, WChar key, uint16 keycode)
 {
 	QueryString *query = this->GetQueryString(wid);
 	if (query == NULL) return ES_NOT_HANDLED;
diff --git a/src/window_gui.h b/src/window_gui.h
index 433ed87292..ce9c062c69 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -488,7 +488,7 @@ public:
 	void UnfocusFocusedWidget();
 	bool SetFocusedWidget(int widget_index);
 
-	EventState HandleEditBoxKey(int wid, uint16 key, uint16 keycode);
+	EventState HandleEditBoxKey(int wid, WChar key, uint16 keycode);
 
 	void HandleButtonClick(byte widget);
 	int GetRowFromWidget(int clickpos, int widget, int padding, int line_height = -1) const;