First note in tie plays during second after changing it via 'Add Note'

1. Open attached score.
2. Click on the second crotchet.
3. Type any note key, except B.
4. Play.

Result: The first note still plays during the second crotchet.

Using MuseScore 1.1 and 2.0 Nightly Build (5119) - Mac 10.6.8.