bug#16348: 24.3.50; Increasing internal-border-width cuts menubar and toolbar on non-toolkit builds

[martin rudalics]

>> What we needed here is some simple switch we can set and which causes
>> the redisplay engine to do a through redisplay instead of trying to be
>> clever and selectively clear/erase some space formerly occupied by a
>> scrollbar, fringe or border.
>
> I believe what you want is to reset the enabled_p flag of each glyph
> row in the current glyph matrix.  But since each window in a GUI
> session has its own glyph matrix, you will need to do that for every
> window on the current frame.
>
> (Maybe there's a variable that has the same effect, I didn't check.)

I'm not sure whether that would suffice.  Currently emacs does all sorts
of erasing and redrawing backgrounds of scrollbars, fringes, borders and
the like.  In many cases, it doesn't get that right.  The only practical
solution I usually see is to resize the frame to some other size and
size it back.  I doubt that this is the same as resetting the enabled_p
flags.

martin