This question is basically reverse of Is there a way to wrap the toolbar buttons to the next row in TinyMCE if the width of the editor is too small?
I have a TinyMCE
Depending on the number of buttons enabled, setting table.mceToolbar to display inline-table can push the editor's width to be too wide.
Instead float each table left so it breaks when the maximum allowable width is reached.
table.mceToolbar {margin-left:3px; float:left}