Forum Insert image popup won't close
 

Hello guys;
after the upgrade to vbulletin 4.2.0 i'm having a problem with the "insert image" popup that after the click on ok(with valid image link) don't close itself. in this case the only way to insert an image is using BB code from the text editor.
this doesn't happen everytime, sometimes it work correctly without a problem....any ideas on the cause of this?
thank you!