Moving from Options or Calendar tabs will sometimes remove my "Today Pane" from the main window. Reselecting "View Today Pane" from below will recover the "Today Pane" but it will be corrupted (events will not be shown). I sometimes have to restart the application several times before it shows up.

I know this isn't easy to replicate. I can't replicate it on demand, but may be others have the same problem.