Please describe exactly what actions triggered the bug
and the precise symptoms of the bug.  If you can, give
a recipe starting from `emacs -Q':

In the quick help buffer (the buffer opened by pressing '?' in the ediff
control panel), there are three columns of help text. The overlays on
the first column extend into the margin as shown in the screenschot
attached. It is easy to trigger the commands by mistake when using a
mouse.