> Steps to reproduce the bug (or maybe it's an intentional feature, but if so, I don't see the purpose):
 > Put just the following in your .emacs file:
 > (setq mouse-autoselect-window t)
 > Start Emacs with no options.
 > Press C-g.
 > Move your mouse pointer across the echo area. Emacs erases "Quit". The desired behavior is to not erase the text; I routinely inadvertently move the pointer across the echo area when moving the pointer to another window (of the window manager, not of Emacs), and when I go back to Emacs, I then have to switch to *Messages* to see what the last message was, rather than just looking at the echo area. Disabling mouse-autoselect-window to avoid the bug isn't an option; the feature is too useful.

We can fix this via the attached patch.  It changes behavior in the
sense that it doesn't run `echo-area-clear-hook' any more for
select-window events.  But if this hook is important it should probably
be run by (message nil) and (message "") anyway.

martin