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Re: Slow tracking of mouse

CC: (BUG lispm) at MIT-AI
There are two effects here.  One is that the mouse is tracked by a
process, written in ordinary Lisp code, rather than, say, microcode.
This means that it can be substantially delayed by paging.  With 128K
the mouse process can easily get paged out if you don't move the
mouse for a while.  No matter how much memory you have, when moving the
mouse into a new window it has to page in data structure associated with
that window, since windows control the mouse when it is in them.

The other effect is that certain things such as pop-up menus "warp" the mouse.
When a menu appears it gets the position of the mouse, then works on appearing
there, then moves the mouse back to there, eliminating any motion you've
done in the meantime.

Note that moving the mouse out of a pop-up menu before it appears if you've
changed your mind won't work because the menu won't go away until the mouse
has been in it and left again and it won't notice it's been in it until
after it appears on the screen.