b=420381, Vista content area dropdowns often don't show dropdown arrow (bandaid); r+sr=roc, a=beltzner

widget/src/windows/nsNativeThemeWin.cpp

@@ -1563,6 +1563,14 @@ nsNativeThemeWin::GetWidgetOverflow(nsIDeviceContext* aContext,
                                     PRUint8 aWidgetType,
                                     nsRect* aResult)
 {
+  /* This is disabled for now, because it causes invalidation problems --
+   * see bug 402381.  The effect of not updating the overflow area is that
+   * for dropdown buttons in content areas, there is a 1px border on 3 sides
+   * where, if invalidated, the dropdown control probably won't be repainted.
+   * This is fairly minor, as by default there is nothing in that area, and
+   * a border only shows up if the widget is being hovered.
+   */
+#if 0
   if (mIsVistaOrLater) {
     /* We explicitly draw dropdown buttons in HTML content 1px bigger
      * up, right, and bottom so that they overlap the dropdown's border
@@ -1580,6 +1588,7 @@ nsNativeThemeWin::GetWidgetOverflow(nsIDeviceContext* aContext,
       return PR_TRUE;
     }
   }
+#endif
 
   return PR_FALSE;
 }