Mac Mail requiring "force quit" with SpamSieve Rule.

Running OS 10.7.1, the latest version of Mac Mail and the latest version of SpamSieve. The installation process for the Mac Mail, in particular, is not an issue. In fact, the entire configuration is quite easy . . . a beginner level. However, I have noticed that when Mac Mail app is activated, so is SpamSieve. That is how it’s designed. However, using Command-Q with the Mail app will make the window disappear, but it still shows open in the dock. Does not matter if I quit SpamSieve first or last, it is still necessary to Force Quit Mac Mail. If I remove the SpamSieve rule from preferences, then Mac Mail quits appropriately. Consequently, I can only deduce that SpamSieve is the culprit and I can reproduce this. So how can this be rectified?

Thanks!

Are you able to launch Mail and then immediately quit it (i.e. no messages are received)? What if it’s in offline mode?

Also, it would be helpful if you could open the Activity Monitor program and select Mail in the list. After you tell it to quit, instead of force-quitting, choose Sample Process from the View menu. Then save the resulting data to a file and send it to me.