I am running 10.5.1, OmniFocus 1.0 and Growl 1.1.2
Question 1: Growl works great - but, if I add an event in OmniFocus, Growl seems to not recognize it unless I quit the OF app and then restart it. If I add the event that should give me a notification it will not notify if I don't quit OF and start it again.
Question 2: Should or can a notification stay on the screen until I've deliberately closed it by clicking on the X?
Question 1: I believe this is likely due to how OmniFocus is adding their notifications to Growl, but I could be wrong.
Question 2: Only if you have specified that it should be sticky, which is the terminology Growl uses for notifications that hang around. This is done in the Applications tab per notification. Default behavior is not to be sticky.