A few things are happening with this on MW1.31 (which were also present in 1.30). I have added the patch in WikiEditor.hooks.php although line 75 doesn't look like the patch link, line 171 does.
Issues seem to be intermittent with not being able to save edits, existing text not showing in editor and both edit bars appearing on the page. The last one varies, sometimes they are stacked on top of each other, sometimes the WikiEditor bar appears at the bottom of the edit window. I want to still have the WikiEditor for editing source.
Any pointers on what could be causing these errors?I've tried changing themes, shutting off the category picker (Extension:MsCatSelect) and it still persists.