Bug 306878. Fire accessible focus events when alt+tabbing back to app. r=parente, sr=jst

accessible/src/base/nsRootAccessible.cpp

@@ -688,6 +688,7 @@ NS_IMETHODIMP nsRootAccessible::HandleEvent(nsIDOMEvent* aEvent)
     if (accessible == this) {
       // Top level window focus events already automatically fired by MSAA
       // based on HWND activities. Don't fire the extra focus event.
+      gLastFocusedNode = mDOMNode;
       return NS_OK;
     }
     FireAccessibleFocusEvent(accessible, targetNode);