Dragging a Time Signature to an imported MIDI file segfaults

GIT commit: 6f951ec

The attached score is based on an imported midi file, slightly edited in MuseScore. If I drag a Time Signature to the first measure, the program segfaults. I use Ubuntu 12.04. Here follows a stack trace:

Segment::add(Rest) there is already an Rest at 65:0:0(30720) track 1
0/1 -> 0/1

Program received signal SIGABRT, Aborted.
0x00007ffff1aff445 in raise () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0 0x00007ffff1aff445 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007ffff1b02bab in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2 0x0000000000adc805 in Segment::add (this=0x60b5eb0, el=0x60b62c0) at /home/johan/Projects/MuseScore/libmscore/segment.cpp:489
#3 0x0000000000b7c624 in TrackList::write (this=0x185bba0, track=1, measure=0x6050bc0, map=0x7fffffffa000)
at /home/johan/Projects/MuseScore/libmscore/range.cpp:474
#4 0x0000000000b7d27d in ScoreRange::write (this=0x7fffffffa000, track=0, m=0x6050bc0)
at /home/johan/Projects/MuseScore/libmscore/range.cpp:619
#5 0x0000000000a3d672 in Score::rewriteMeasures (this=0x56f1a00, fm=0x5936730, lm=0x5a08870, ns=...)
at /home/johan/Projects/MuseScore/libmscore/edit.cpp:429
#6 0x0000000000a3d92a in Score::rewriteMeasures (this=0x56f1a00, fm=0x5936730, ns=...)
at /home/johan/Projects/MuseScore/libmscore/edit.cpp:474
#7 0x0000000000a3e0d5 in Score::cmdAddTimeSig (this=0x56f1a00, fm=0x59bfbd0, staffIdx=0, ts=0x1853b10, local=false)
at /home/johan/Projects/MuseScore/libmscore/edit.cpp:568
#8 0x0000000000a9a066 in Measure::drop (this=0x59bfbd0, data=...) at /home/johan/Projects/MuseScore/libmscore/measure.cpp:1503
#9 0x00000000009b6d5c in ScoreView::dropEvent (this=0x591d8c0, event=0x7fffffffb0a0)
at /home/johan/Projects/MuseScore/mscore/dragdrop.cpp:507
#10 0x00007ffff4435491 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#11 0x00000000006a0761 in ScoreView::event (this=0x591d8c0, event=0x7fffffffb0a0) at /home/johan/Projects/MuseScore/mscore/scoreview.cpp:3728
#12 0x00007ffff43e4894 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#13 0x00007ffff43e9c5f in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#14 0x00007ffff3932e9c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#15 0x00007ffff446f163 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#16 0x00007ffff44706f3 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#17 0x00007ffff4473488 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#18 0x00007ffff3932f6c in QCoreApplicationPrivate::sendThroughApplicationEventFilters(QObject*, QEvent*) ()
from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#19 0x00007ffff43e4806 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#20 0x00007ffff43ea0bf in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#21 0x00007ffff3932e9c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#22 0x00007ffff43e5862 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer&, bool)
() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#23 0x00007ffff4464bf5 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#24 0x00007ffff4463bae in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#25 0x00007ffff448d0d2 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#26 0x00007fffefaa0d53 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#27 0x00007fffefaa10a0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#28 0x00007fffefaa1164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#29 0x00007ffff39623bf in QEventDispatcherGlib::processEvents(QFlags) ()
---Type to continue, or q to quit---
from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#30 0x00007ffff448cd5e in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#31 0x00007ffff3931c82 in QEventLoop::processEvents(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#32 0x00007ffff3931ed7 in QEventLoop::exec(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#33 0x00007ffff4473183 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#34 0x00007ffff43f6613 in QDrag::start(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#35 0x00000000007c829f in Palette::mouseMoveEvent (this=0x55418d0, ev=0x7fffffffcfd0) at /home/johan/Projects/MuseScore/mscore/palette.cpp:357
#36 0x00007ffff4435178 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#37 0x00000000007c9a85 in Palette::event (this=0x55418d0, ev=0x7fffffffcfd0) at /home/johan/Projects/MuseScore/mscore/palette.cpp:629
#38 0x00007ffff43e4894 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#39 0x00007ffff43ea0bf in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#40 0x00007ffff3932e9c in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#41 0x00007ffff43e5862 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer&, bool)
() from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#42 0x00007ffff4464bf5 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#43 0x00007ffff4463bae in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#44 0x00007ffff448d0d2 in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#45 0x00007fffefaa0d53 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#46 0x00007fffefaa10a0 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#47 0x00007fffefaa1164 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#48 0x00007ffff39623bf in QEventDispatcherGlib::processEvents(QFlags) ()
from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#49 0x00007ffff448cd5e in ?? () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
#50 0x00007ffff3931c82 in QEventLoop::processEvents(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#51 0x00007ffff3931ed7 in QEventLoop::exec(QFlags) () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#52 0x00007ffff3936f67 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
#53 0x00000000007a1ae4 in main (argc=1, av=0x7fffffffe238) at /home/johan/Projects/MuseScore/mscore/musescore.cpp:2475
(gdb)