0.9.4 crashes when inserting a note

MuseScore 0.9.4 crashes when the user forgets to select a note length before inserting notes.

Steps to reproduce:

1. Create a new score.
2. Hit the "N" key for note input mode. See that no note length is selected by default.
3. Click on the staff as if you were inserting a note. Nothing happens.
4. Click again – the program exits with
/usr/bin/mscore: line 27: 5508 Segmentation fault $MSCORE "$@"

OS: Debian GNU/Linux squeeze/sid
Kernel: 2.6.26 i686
Qt: 4.5.1