diff --git a/src/window_gui.h b/src/window_gui.h
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -491,7 +491,7 @@ public:
 	bool SetFocusedWidget(int widget_index);
 
 	EventState HandleEditBoxKey(int wid, WChar key, uint16 keycode);
-	virtual void InsertTextString(int wid, const char *str);
+	virtual void InsertTextString(int wid, const char *str, bool marked, const char *caret);
 
 	void HandleButtonClick(byte widget);
 	int GetRowFromWidget(int clickpos, int widget, int padding, int line_height = -1) const;