Problems creating tuplets

I don't know if it's known as a nested tuplet? Not sure if you should be allowed to create so many either?

1. Create 4/4 piano score.
2. Create triplet based on a semibreve.
3. Whilst in Note Entry, repeatedly hit for a triplet.

Result: Crashes.

MuseScore 1.0 and Mac 10.4.11.

In the trunk, it's different:

1. Create 4/4 piano score.
2. Create triplet based on semibreve rest.
3. Create another triplet
(Result: Bracket is a problem)
4. Press right and create triplets a few times.

Result: Crash.

MuseScore 2.0 nightly build (3996) and Mac 10.4.11.