RE: [simon.marshall@misys.com: mouse-autoselect-window needs a de lay]

["Marshall, Simon" <simon.marshall@misys.com>]

Hi Martin, I occasionally get this (taken from *Messages*):

mouse-autoselect-window-start: Wrong type argument: numberp, nil

I just caught it with debug-on-error, though I'm not sure quite how to read
it as it looks like 2 errors have occurred.  The way I read it, we are in
the process of switching to the *Backtrace* window when the error
(presumably) happened again:

Debugger entered--Lisp error: (wrong-type-argument numberp nil)
  window-at(nil nil #<frame test2/CONTRACT.in 0xd1a200>)
  mouse-autoselect-window-start()
  handle-select-window((select-window (#<window 47 on *Backtrace*>)))
  call-interactively(handle-select-window)

But it is kind-of what I guessed, that the error is thrown by window-at
because mouse-position returns nil for X and Y.

I can fairly easily reproduce this with emacs -Q if I move from the selected
first frame to a second frame and then off that second frame quickly when
(a) the second frame has split windows, (b) the second frame's selected
window (ie, when the second frame is selected) and its point is covered by
the first frame.

The amount of time spent in the second frame does not seem to depend on
mouse-autoselect-window.  Maybe it has more to do with whether Emacs gets
the chance to get some info out of X before the mouse has moved off the
second frame.  I use Solaris CDE on a PC running Exceed, which may
complicate/slow things.

Maybe the only fix is to be tolerant of nil for X and Y from mouse-position.

Simon.