#56 highlighted line obscured by message window

[Oswald Buddenhagen]

when selecting messages in the message window, it
should be made sure that the highlighted line is in a part
of the target window that is not obscured by the
(non-zoomed) message window itself.
alternatively, make the message window shrink the editor
windows for the time it is open. if everything would be as
expected, this would mean just unzooming them all.
however, this is too simplistic to work for me.