Allow removal of remaining instrument selected
1. 'Create New Score'.
2. At the instrument selection step, add 'Piano'.
3. From the column of instruments selected, click on 'Piano'.
Desired result: You can remove what is the only instrument, but 'Next' and 'Finish' are disabled.
Actual result: You can't remove the one selected instrument.
Using MuseScore 2.0 Nightly Build (279c5e4) - Mac 10.7.4.