Bug#929090: xfwm4: ButtonPress event from Tk triggers Enter and Leave events

[Michael Lange <klappnase@web.de>]

Package: xfwm4
Version: 4.12.4-1
Severity: normal

Dear Maintainer,

in applications using the Tk toolkit each time a mouse button is pressed
additional Enter and Leave events are triggered for no apparent reason. A
minimal wish script that illustrates this:

#!/usr/bin/env wish
frame .f -bg yellow -width 400 -height 300
pack .f -fill both -expand 1
bind .f <Button-1> {puts "Button-1 event"}
bind .f <Enter> {puts "Enter event"}
bind .f <Leave> {puts "Leave event"}

I admit I am not really sure to which package this bug report should be
addressed.
These "bogus" Enter and Leave events do not occur with Gnome, KDE or Mate or
some older light-weight WMs like WindowMaker, FvWm or IceWm, so I believe it is
unlikely that it is a Tk bug. Otoh the same or similar behavior has also been
observed with Openbox/Lxde and awesome.
This behavior does still persist in the versions of Xfce/xfwm currently in
debian Sid (tested yesterday).
The bug was first reported on the tkinter-discuss mailing list and has been
discussed here:

https://mail.python.org/pipermail/tkinter-discuss/2019-May/004082.html

and on debian-user here:

https://lists.debian.org/debian-user/2019/05/msg00668.html

Best regards

Michael



-- System Information:
Debian Release: 9.9
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'proposed-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.9.0-9-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages xfwm4 depends on:
ii  libc6                     2.24-11+deb9u4
ii  libcairo2                 1.14.8-1
ii  libdbus-glib-1-2          0.108-2
ii  libgdk-pixbuf2.0-0        2.36.5-2+deb9u2
ii  libglib2.0-0              2.50.3-2
ii  libgtk2.0-0               2.24.31-2
ii  libpango-1.0-0            1.40.5-1
ii  libstartup-notification0  0.12-4+b2
ii  libwnck22                 2.30.7-5.1
ii  libx11-6                  2:1.6.4-3+deb9u1
ii  libxcomposite1            1:0.4.4-2
ii  libxdamage1               1:1.1.4-2+b3
ii  libxext6                  2:1.3.3-1+b2
ii  libxfce4ui-1-0            4.12.1-2
ii  libxfce4util7             4.12.1-3
ii  libxfconf-0-2             4.12.1-1
ii  libxfixes3                1:5.0.3-1
ii  libxrandr2                2:1.5.1-1
ii  libxrender1               1:0.9.10-1

Versions of packages xfwm4 recommends:
ii  librsvg2-common  2.40.16-1+b1

Versions of packages xfwm4 suggests:
ii  xfce4         4.12.3
ii  xfwm4-themes  4.10.0-2

-- no debconf information