mousepad crashed with SIGSEGV in g_type_check_instance_is_a()

Status changed to 'Confirmed' because the bug affects multiple users.

StacktraceTop:
 g_type_check_instance_is_a (type_instance=0x7f58dac02f20, iface_type=<optimized out>) at /build/buildd/glib2.0-2.43.92/./gobject/gtype.c:4016
 gtk_tree_view_drag_motion (widget=0x7f58dac02f20, context=0x7f58da20feb0, x=-697400160, y=0, time=3659771024) at /build/buildd/gtk+3.0-3.14.9/./gtk/gtktreeview.c:7998
 ?? ()
 ?? ()
 ?? () from /tmp/apport_sandbox_bT0ai1/usr/lib/x86_64-linux-gnu/libgdk-3.so.0

Thank you for your report!

However, processing it in order to get sufficient information for the
developers failed (it does not generate a useful symbolic stack trace). This
might be caused by some outdated packages which were installed on your system
at the time of the report:

libgcc1 version 1:5-20150309-1ubuntu3 required, but 1:5-20150321-1ubuntu3 is available
systemd version 219-4ubuntu8 required, but 219-4ubuntu10 is available
libsystemd0 version 219-4ubuntu8 required, but 219-4ubuntu10 is available
no debug symbol package found for libsystemd0
gcc-5-base version 5-20150309-1ubuntu3 required, but 5-20150321-1ubuntu3 is available
libdbus-1-3 version 1.8.12-1ubuntu3 required, but 1.8.12-1ubuntu4 is available
libgtk-3-common version 3.15.5~20150206.r1+git0b06b1e-0ubuntu1 required, but 3.14.9-0ubuntu1 is available
cgmanager version 0.36-2ubuntu1 required, but 0.36-2ubuntu3 is available
no debug symbol package found for xdg-user-dirs
libapt-inst1.5 version 1.0.9.3ubuntu1 required, but 1.0.9.7ubuntu3 is available
dbus version 1.8.12-1ubuntu3 required, but 1.8.12-1ubuntu4 is available
no debug symbol package found for dmsetup
no debug symbol package found for libisc-export95
udev version 219-4ubuntu8 required, but 219-4ubuntu10 is available
libcgmanager0 version 0.36-2ubuntu1 required, but 0.36-2ubuntu3 is available
libstdc++6 version 4.9.2-10ubuntu10 required, but 4.9.2-10ubuntu11 is available
no debug symbol package found for libdevmapper1.02.1
no debug symbol package found for libirs-export91
apt version 1.0.9.3ubuntu1 required, but 1.0.9.7ubuntu3 is available
init-system-helpers version 1.22ubuntu4 required, but 1.22ubuntu5 is available
libgtk-3-0 version 3.15.5~20150206.r1+git0b06b1e-0ubuntu1 required, but 3.14.9-0ubuntu1 is available
libpam-systemd version 219-4ubuntu8 required, but 219-4ubuntu10 is available
no debug symbol package found for debianutils
libapt-pkg4.12 version 1.0.9.3ubuntu1 required, but 1.0.9.7ubuntu3 is available
libudev1 version 219-4ubuntu8 required, but 219-4ubuntu10 is available
no debug symbol package found for libisccfg-export90
no debug symbol package found for libdns-export100
libgtk-3-bin version 3.15.5~20150206.r1+git0b06b1e-0ubuntu1 required, but 3.14.9-0ubuntu1 is available
libatk1.0-0 version 2.15.4-0ubuntu1~ppa0 required, but 2.14.0-1ubuntu1 is available
apt-utils version 1.0.9.3ubuntu1 required, but 1.0.9.7ubuntu3 is available
libatk1.0-data version 2.15.4-0ubuntu1~ppa0 required, but 2.14.0-1ubuntu1 is available
multiarch-support version 2.21-0ubuntu2 required, but 2.21-0ubuntu4 is available
libc6 version 2.21-0ubuntu2 required, but 2.21-0ubuntu4 is available
no debug symbol package found for perl-base
no debug symbol package found for sed
libgudev-1.0-0 version 1:219-4ubuntu8 required, but 1:219-4ubuntu10 is available
no debug symbol package found for libgudev-1.0-0
no debug symbol package found for iproute2
gcc-4.9-base version 4.9.2-10ubuntu10 required, but 4.9.2-10ubuntu11 is available
no debug symbol package found for gcc-4.9-base
libgcc1 version 1:5-20150309-1ubuntu3 required, but 1:5-20150321-1ubuntu3 is available
libdbus-1-3 version 1.8.12-1ubuntu3 required, but 1.8.12-1ubuntu4 is available
lib...