Bug#834595: mate-desktop: cursor doesn't follow finger on the touchscreen if second display is attached

[Oliver Sander]

Package: mate-desktop
Version: 1.14.1-1
Severity: normal

I am not quite sure what package to report this bug against.  Apologies if I picked
the wrong one.

I have a ThinkPad Yoga 12, which has a touchscreen.  In a normal MATE session, I can
move my finger on the touchscreen, and the cursor will follow the finger.  Just like
it is supposed to.

However, I now plug in an external display.  By default, it is supposed to be physically
located to the right of my primary display, i.e., my desktop is now twice as wide;
the left part is on my built-in display, the right part on the external one.
In this situation, the code that computes the cursor position from my finger position
on the touchscreen is wrong: when I move my finger from the left edge to to the right
edge of my primal display, the cursor moves from the left boundary to the right boundary
of the entire virtual desktop.  In particular, if I touch the screen in the right half,
the cursor appears on the other display. 


-- System Information:
Debian Release: stretch/sid
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'testing')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.6.0-1-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages mate-desktop depends on:
ii  hicolor-icon-theme        0.15-1
ii  libatk1.0-0               2.20.0-1
ii  libc6                     2.23-4
ii  libcairo-gobject2         1.14.6-1+b1
ii  libcairo2                 1.14.6-1+b1
ii  libgdk-pixbuf2.0-0        2.34.0-1
ii  libglib2.0-0              2.48.1-2
ii  libgtk-3-0                3.20.7-1
ii  libmate-desktop-2-17      1.14.1-1
ii  libpango-1.0-0            1.40.1-1
ii  libpangocairo-1.0-0       1.40.1-1
ii  libstartup-notification0  0.12-4
ii  libxrandr2                2:1.5.0-1
ii  mate-desktop-common       1.14.1-1
ii  mate-user-guide           1.14.0-1
ii  python                    2.7.11-2
ii  python-requests           2.10.0-2

mate-desktop recommends no packages.

mate-desktop suggests no packages.

-- no debconf information