IE9: js error when closing the popup.
IE9: js error when closing the popup.

Steps to reproduce:
1. Open demo page in ie9: http://demos.badsyntax.co/tinymce-jqueryui-popups/ 
2. Open 'Edit HTML Source' popup
3. Press cancel button
4. JS error happens

The root of the problem is jquery's dialog destroy method. It removes iframe from dialog element and places it into document.body. This causes iframe to reload.
badsyntax/tinymce-custom-inlinepopups