[trunk] "Reset Stretch" crashes if no selection
Setup: trunk rev. 3877 under Ubuntu 10.4, Qt lib 4.6.2 (but the issue is independent from platform)
1. Open any score
2. Make sure there is no selection
3. Select "Layout | Reset Stretch" from main menu
Note: two patches have been sent to the dev mailing list, for the developers to choose the best approach.