diff --git a/src/window_gui.h b/src/window_gui.h
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -349,6 +349,7 @@ public:
 	virtual const char *GetCaret() const;
 	virtual const char *GetMarkedText(size_t *length) const;
 	virtual Point GetCaretPosition() const;
+	virtual Rect GetTextBoundingRect(const char *from, const char *to) const;
 
 	void InitNested(WindowNumber number = 0);
 	void CreateNestedTree(bool fill_nested = true);