ignore mouse-wheel press during rotation

[Drew Adams]

This might be considered a bug fix request, but it is probably better seen
as feature request. It concerns mice that have a wheel that can be rotated
or pressed (e.g. clicked). In the latter case, the wheel is (usually?
always?) treated as mouse-2.

The problem (annoyance) is that with many (all?) such mice it is easy to
accidentally press the wheel while trying to rotate it (the rotation finger
movement ends similarly to a press movement). In Emacs, this results in a
rotation (wheel) event followed by a mouse-2 event, which is rarely what you
want. This can be disorienting for a gnubie (e.g. unexpected pasted text),
and it is anyway annoying for oldbies.

Note that this is less of a problem (nonexistent?) in other applications,
which do not use mouse-2 the way Emacs does. For example, you don't notice
this problem in common Web browsers because you generally use mouse-1, not
mouse-2, for clicking and press-dragging. Emacs makes heavy use of mouse-2,
so the problem arises more frequently.

It would be great to remove this annoyance. This could probably be done by
ignoring mouse-2 events during and shortly after wheel-rotation events. This
might mean something like the following:

1. Ignore mouse-2 events between two mouse wheel rotation events.

2. Ignore a mouse-2 event following a mouse wheel rotation event
   within some (configurable) duration.

Perhaps #1 is not necessary or desirable. #2 should be sufficient, I think
(but I'm not sure).

WDOT? Is this something that could be tackled before the release? If not,
could we put it on the to-do list for after the release?