Until updating today of 3.9 RC-1, I could see 45 icons in the TinyMCE on the settings page, but only 27 showed on the Visual editor page.
After updating today there are 33 icons showing on the Visual editor page plus 4 empty spaces, which on hovering show Insert/Edit Attributes,Edit CSS, Horizontal Rule and Find.
I can edit text on this page, buy Ctrl+Z does not work.
Firebug Console shows:
"Deprecated TinyMCE API call: <target>.onNodeChange.add(..)"