I had the same problem. For me, adjusting the toolbars in TinyMCE Advanced fixed it. (Settings > TinyMCE Advanced > TinyMCE Buttons Arrangement.) Drag and drop buttons. I moved any buttons that overflowed onto the next line down to either a line that had room or a new line. There does seem to be a limit to the number of buttons that will display correctly.
Another solution that I came across on the web was to drag the Publish and Attributes sections down below the editor (the cursor turns into a 4-way move arrow when hovered over those sections and you can drag and drop them to the left and down to drop them in the area below the editor.)
Hope this helps.