[FF] Unable to open context menu on flash

[Garry Yao]

Open the ajax sample with Firefox.

1. Click the Create Editor button.
2. Click on the Flash button to open the Flash Dialog.
3. Enter the URL for the flash object and click OK.
4. Click the Remove Editor button.
5. Click the Create Editor button again.
6. Right click on the flash object to open context menu.

• Actual Result: Observe that it's not possible to open context menu.

[Garry Yao]

Yet another DUP of #4552.