Fix context menus in thread pane on Linux by making sure not to re-use an event struct (and its changed event flags) after dispatching it. Bug 179172, r=varga, sr=blizzard.

widget/src/gtk/nsWidget.cpp

@@ -1868,9 +1868,9 @@ nsWidget::OnButtonPressSignal(GdkEventButton * aGdkButtonEvent)
   // if we're a right-button-down on linux, we're trying to
   // popup a context menu. send that event to gecko also.
   if (eventType == NS_MOUSE_RIGHT_BUTTON_DOWN) {
-    eventType = NS_CONTEXTMENU;
-    InitMouseEvent(aGdkButtonEvent, event, eventType);
-    DispatchMouseEvent(event);
+    nsMouseEvent contextMenuEvent;
+    InitMouseEvent(aGdkButtonEvent, contextMenuEvent, NS_CONTEXTMENU);
+    DispatchMouseEvent(contextMenuEvent);
   }
 
   Release();

widget/src/gtk2/nsWindow.cpp

@@ -1367,8 +1367,9 @@ nsWindow::OnButtonPressEvent(GtkWidget *aWidget, GdkEventButton *aEvent)
 
     // right menu click on linux should also pop up a context menu
     if (eventType == NS_MOUSE_RIGHT_BUTTON_DOWN) {
-        InitButtonEvent(event, NS_CONTEXTMENU, aEvent);
-        DispatchEvent(&event, status);
+        nsMouseEvent contextMenuEvent;
+        InitButtonEvent(contextMenuEvent, NS_CONTEXTMENU, aEvent);
+        DispatchEvent(&contextMenuEvent, status);
     }
 }