How can I only show Summary tasks in the Calendar

[ERahh]

I almost think I have a bug or I'm doing something blatantly wrong...when you are in the Gant chart view and need a high level overview of the project at the summary level you can quicly do a filter by summary tasks... to only show summary task items...

I need/want to do this at the calendar view as well .... but when I click on the filter to show only summary tasks the view goes blank ... as if it considers there to be no summary tasks....

Any info would be greatly appreciated!!!

ER