Using Featured image: post state is set dirty, even when no changes to content

[jacobcoens]

Browser: IE

Behavior:
When editing a post and clicking 'Set featured image', a (thickbox) popup opens. When cancelling, the MCE state is dirty, even when no changes to the content have been made.
This is causing the message 'Are you sure you want to navigate away from this page?' to be displayed when navigating to another page.

Cause:
This happens in IE because a bookmark is created to store the caret position.

Fix:
Remember the 'dirty' state of MCE, and re-apply it to the editor after creating the bookmark.

In wp-admin/js/media-upload.dev.js, replace line 62-68 with below:

var ed;

if ( typeof tinyMCE != 'undefined' && tinymce.isIE && ( ed = tinyMCE.activeEditor ) && !ed.isHidden() ) {

var dirty = ed.isDirty();
ed.focus();
ed.windowManager.insertimagebookmark = ed.selection.getBookmark();
ed.isNotDirty = !dirty;

}

Can we close this ticket in favour of the new media modal?

Could not reproduce the original bug using IE 8 neither in 3.2.1 (reported version) nor in 3.5-beta3.