bug#12419: Mouse click changes layout

[martin rudalics]

>> Can you improve the behavior by changing the value of
>> `resize-mini-windows'?
>
> It has it's default value of grow-only.  I like the feature and wouldn't
> want to turn it off.

I meant for testing purposes only.

> I guess the annoying thing is that the resizing happens on mouse-down
> and side-ways scrolling on mouse-drag, i.e. in the middle of my
> operation.  If it were deferred till mouse-up (or till I drag to outside
> of the window to force scrolling), then it would be consistent with
> regard to where I clicked.

You could try to inject some code at the beginning of
`window--resize-root-window-vertically' that writes a backtrace into a
buffer.  This way we could get some information about the kind of
mouse-event that caused the resizing.

martin