Buttons unintentionally visible in some steps of score creation

1. Open MuseScore.
2. 'Create New Score'.
(Result: 'Back' is available, despite no previous step.)
3. At text information, click 'Next'.
(Result: 'Next' is visible in instrument selection, despite no instrument selected.)
4. At instrument selection, choose one.
5. Click 'Next'.
6. At key signature selection, click 'Next'.

Expected result: In the final step in the creation of a new score (time signature), the next button should be greyed out.
Actual result: The next button is visible, but not clickable.

Discussion: Only reproducible sometimes in each program launch. If you click elsewhere, then back on MuseScore, the unintentionally visible button will grey out. I'm not sure if 'Finish' should be present at some stages, unless you want an empty score.

Using MuseScore 2.0 Nightly Build (4766) - Mac 10.6.8.