bug#12419: Mouse click changes layout

[martin rudalics <rudalics@gmx.at>]

 >> Where do you see that?  Can you give an example?
 >
 > Try the recipe I showed earlier in this thread with Emacs 23.3, but
 > use 1000 instead of 380, and you will see that only the last part of
 > the echo-area message is shown.

max-mini-window-height is a variable defined in `xdisp.c'.
Its value is 0.25

Documentation:
Maximum height for resizing mini-windows (the minibuffer and the echo area).
If a float, it specifies a fraction of the mini-window frame's height.
If an integer, it specifies a number of lines.

You can customize this variable.

This variable was introduced, or its default value was changed, in
version 23.1 of Emacs.

 >> Then put a one-line window at the bottom of your frame and resize the
 >> minibuffer.  At the time it sizes back the one-line window has grown.
 >
 > OK, but why is that a problem grave enough to be concerned about?
 > Using Ediff in such a way is non-standard, so won't be a problem for
 > most users.  And even in this configuration, what is so bad about
 > this?

 From the number of code lines he spent to handle this problem, I
conclude that it was bad enough for Gerd.

 >>  > If the lowest window is large enough, why not show more of
 >>  > the echo-area message, instead of always showing only the last N lines?
 >>
 >> I don't understand you.  As far as minibuffer resizing is concerned, you
 >> can show any number of lines in the minibuffer as long as you don't try
 >> to delete other windows.  So the N lines restriction you see must come
 >> from somewhere else.
 >
 > Maybe it does, but I tried that with "emacs -Q", so the number of such
 > other places is severely limited ;-)

It is.

 > AFAICS, with your patch the minibuffer is never resized to show more
 > than 9 lines, with the default size of the frame which can show 33
 > text lines.  This is so even if I do _not_ split the frame into 2
 > windows, one below the other, but instead invoke 'message' from the
 > original window configuration displayed by "emacs -Q", where there's a
 > single window showing the "*scratch*" buffer.  Try this:
 >
 >   emacs -Q
 >   (message (make-string 1000 ?a))
 >   C-x C-e
 >
 > How many lines and how many a's do you see in the echo area?

9 lines - so our Emacsen are created equal.  Nothing can beat evolution ;-)

martin