Long HTML in source mode in IE8 scrolls up when editor loses focus

[Kevin Williams]

Steps to reproduce:

• Use MSIE 8 as your browser; ensure compatibility mode is disabled
• Visit the latest nightly build (I used ​http://nightly.ckeditor.com/5000/_samples/replacebyclass.html)
• View the page source and copy the HTML to your clipboard (any medium-large HTML page will do) then close the source view
• Click the Source button in the editor instance
• Paste the contents of the clipboard buffer into the editor pane
• Scroll to the bottom of the editor. You will now see something similar to the attached file "scrollpos_orig.png"
• Now click the cursor somewhere outside the editor area, e.g. on the window body.

Expected Behavior:

Editor scroll position does not change (screen appearance remains the same)

Actual Behavior:

Editor scrolls upward an arbitrary amount toward the top of the source document. Repeatedly clicking inside/outside the editor pane scrolls further up the document in most cases. See attached screenshot, "scrollpos_moved.png".

Browser/OS:

Microsoft Internet Explorer 8 (I am using release 8.0.6001.18702) on Windows XP SP2

Notes:

This was previously reported by someone else in defect #4775 (and possibly others), which was marked as invalid. However, both that and this defect have the same root cause, which is a callback executed in the "source" textarea when the blur event is fired. The change that "fixed" #4775 appears to be the removal of manually firing onblur when onmouseout fired, but it did not resolve the core issue.

[Kevin Williams]

Appearance of the scroll position before clicking outside the editor

[Kevin Williams]

Appearance of the scroll position after clicking outside the editor pane

[Kevin Williams]

Looks like this defect has already been reported multiple times in #4761 , #4817 , #4762 , and possibly others. I am closing and marking as duplicate.