RE: [PATCH] RE: Ghost cursors (was: RE: alt-tab: client window receives tab / pressing both...)

["Harold Hunt" <huntharo at msu dot edu>]

Stuart,

Naturally, now that I have applied the -lesspointer patch I have remembered
why we switched away from hiding the Windows mouse cursor when we were
inactive.  The reason goes like this:

1) User has a Cygwin/XFree86 window that is away from the task bar.

2) User activates the Cygwin/XFree86 window to bring it to the top, though
the window is small (say 640x480 on a 1024x768 screen) so it doesn't cover
all other windows.

3) Now the user activates another application via the taskbar, say a Cygwin
bash shell.  This other application does not completely cover the
Cygwin/XFree86 window.

4) The user moves the mouse into the Cygwin/XFree86 window, without
clicking, thus hiding the mouse cursor but not activating the Cygwin/XFree86
window.

5) A popup window from another application grabs the focus and either the
popup window covers the area underneath the mouse or the user moves the
mouse into the popup window in such a way as to not cross the non-client
area of the Cygwin/XFree86 window.

6) At this point Cygwin/XFree86 should no longer be hiding the mouse cursor
because a) we aren't active and b) the mouse cursor is not over our window.
However, our only way of detecting that the mouse pointer has left our
window when we are inactive is to watch for the non-client area mouse
messages.  In this test case we never see a non-client area mouse message so
we never show the cursor.


I can't remember if this actually causes the Windows cursor to not be shown
for the popup window or not.  It may depend entirely on the version of
Windows, or it may depend on the popup window, etc.

All I can say is that the -lesspointer parameter is your guy's baby and I'll
send people to you if they complain about -lesspointer causing their cursor
to disappear over other Windows windows.  :)

I think the very simple method to make -lesspointer more robust is to call
TrackMouseEvent with the TME_LEAVE flag when we get our first client area
mouse message.  Then when the mouse leaves our client area (and I'm assuming
that a popup covering the area underneath the mouse qualifies as leaving the
client area) we will get a WM_MOUSELEAVE message.  We can simply show the
Windows mouse cursor if it is being hidden at that time.  Simple, eh?


Harold