#1640 phantom events with tk_popup

[Torsten Rottmann]

with Tcl/Tk 8.4.2 on Microsoft Windows Platforms
the attached file "popup.tcl" will demonstrate
the generation of phantom events to unterlying
toplevel.

I verified this a least for the ButtonRelease
and BottonMotion type of events.

The BottonMotion events will always be generated,
the ButtonRelease only, if you hold Button-1
pressed while moving around in the popup.

I think these events should not be generated
(in fact they trigger false actions in my
programs), and in X11 they are correctly suppressed.

I also checked the "tk_popup" code in
lib/tk8.4.2/menu.tcl. Adding addional grabs there
help in the case of the Motion Events, but the
(most annoying) ButtonRelease keeps fooling me.

[Torsten Rottmann]

This triggers phantom events on windows platforms