Added some debug code to inform of incorrect removal of widgets.

git-svn-id: svn+ssh://svn.code.sf.net/p/supertuxkart/code/main/trunk@5757 178a84e3-b1eb-0310-8ba1-8eac791a3b58

src/guiengine/screen.cpp

@@ -218,6 +218,14 @@ void Screen::manualAddWidget(Widget* w)
 void Screen::manualRemoveWidget(Widget* w)
 {
     assert(m_magic_number == 0xCAFEC001);
+#ifdef DEBUG
+    if(!m_widgets.contains(w))
+    {
+        fprintf(stderr, "Widget '%d' not found in screen when removing.\n",
+                w->m_id);
+        fprintf(stderr, "This can be ignored, but is probably wrong.\n");
+    }
+#endif
     m_widgets.remove(w);
 }   // manualRemoveWidget