Can't enable Pan roll during playback
Select a measure, right click on it and choose Panroll Editor.... In the Panroll Editor toolbar, there's a button Pan roll during playback. It's enabled by default. Click this button to disable it. Now click it to enable this feature again.
Result: it's not possible to enable the feature again, even if we close MuseScore and open it again.
Config: MuseScore 75d9e76 on Xubuntu 14.10.