more GetDefaultAttributesFromGTKWidget fixes

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@28802 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk1/radiobut.cpp

@@ -237,9 +237,12 @@ wxVisualAttributes
 wxRadioButton::GetClassDefaultAttributes(wxWindowVariant WXUNUSED(variant))
 {
     wxVisualAttributes attr;
+    // NB: we need toplevel window so that GTK+ can find the right style
+    GtkWidget *wnd = gtk_window_new(GTK_WINDOW_TOPLEVEL);
     GtkWidget* widget = gtk_radio_button_new_with_label(NULL, "");
+    gtk_container_add(GTK_CONTAINER(wnd), widget);
     attr = GetDefaultAttributesFromGTKWidget(widget);
-    gtk_widget_destroy(widget);
+    gtk_widget_destroy(wnd);
     return attr;
 }