Double click issue with 3.4.2 makes WHOLE page uneditable in FF

[Andrew]

When you double click the image button or any other button in the toolbar the background overlay is placed above the open dialog making the user unable to do anything on the page. And the user is only left with the option to kill the page or hit the backspace button.

In the world of CMS such as Joomla this is not good as this means the user will lose all they work they have done so far in the editted article as there is no way to save the article.

Actual results: background overlay placed above the open dialog effectively freezing the page.

Expected results: Background overlay should be below the open dialog

You can reproduce this by going to the demo page on this site and double clicking the image button in the toolbar

[Alfonso Martínez de Lizarrondo]

dup of #6390