--- a/src/misc_gui.cpp	Tue Feb 13 09:54:37 2007 +0000
+++ b/src/misc_gui.cpp	Tue Feb 13 10:17:24 2007 +0000
@@ -498,7 +498,7 @@
 		COPY_IN_DPARAM(0, _errmsg_decode_params, lengthof(_errmsg_decode_params));
 		DrawWindowWidgets(w);
 		COPY_IN_DPARAM(0, _errmsg_decode_params, lengthof(_errmsg_decode_params));
-		if (!IsWindowOfPrototype(w, _errmsg_face_widgets)) {
+		if (!w->IsWindowOfPrototype(_errmsg_face_widgets)) {
 			DrawStringMultiCenter(
 				120,
 				(_errmsg_message_1 == INVALID_STRING_ID ? 25 : 15),

--- a/src/station_gui.cpp	Tue Feb 13 09:54:37 2007 +0000
+++ b/src/station_gui.cpp	Tue Feb 13 10:17:24 2007 +0000
@@ -683,7 +683,7 @@
 		}
 	} while (pos > -5 && ++i != NUM_CARGO);
 
-	if (IsWindowOfPrototype(w, _station_view_widgets)) {
+	if (w->IsWindowOfPrototype(_station_view_widgets)) {
 		char *b = _userstring;
 		bool first = true;
 
@@ -742,7 +742,7 @@
 			w->SetDirty();
 
 			/* toggle height/widget set */
-			if (IsWindowOfPrototype(w, _station_view_expanded_widgets)) {
+			if (w->IsWindowOfPrototype(_station_view_expanded_widgets)) {
 				w->AssignWidgetToWindow(_station_view_widgets);
 				w->height = 110;
 			} else {

--- a/src/window.cpp	Tue Feb 13 09:54:37 2007 +0000
+++ b/src/window.cpp	Tue Feb 13 10:17:24 2007 +0000
@@ -922,9 +922,9 @@
 //	}
 //}
 
-bool IsWindowOfPrototype(const Window *w, const Widget *widget)
+bool Window::IsWindowOfPrototype(const Widget *widgets) const
 {
-	return (w->original_widget == widget);
+	return (original_widget == widgets);
 }
 
 /* Copies 'widget' to 'w->widget' to allow for resizable windows */

--- a/src/window.h	Tue Feb 13 09:54:37 2007 +0000
+++ b/src/window.h	Tue Feb 13 10:17:24 2007 +0000
@@ -387,6 +387,7 @@
 	static Window* FindById(WindowClass cls, WindowNumber num);
 	static void SetDirtyById(WindowClass cls, WindowNumber num);
 
+	bool IsWindowOfPrototype(const Widget *widgets) const;
 	int GetMenuItemIndex(int x, int y) const;
 	void ResizeWindow(int x, int y);
 
@@ -730,7 +731,6 @@
 //Window *BringWindowToFrontById(WindowClass cls, WindowNumber number);
 Window *FindWindowFromPt(int x, int y);
 
-bool IsWindowOfPrototype(const Window *w, const Widget *widget);
 //Window *AllocateWindow(
 //							int x,
 //							int y,