My reminders list shows several (but not all) reminders I have checked as completed some weeks ago. Naturally I have uncheked the option list "show all completed items"
I'm using iCal on 10.7.1 for the client of a Calendar Server Lion 10.7.1
I appreciate any lights on this.
If you go to "Preferences" and then "Advanced," you can check the box that says "Hide Reminders __ Days after they have been completed" In the text box, enter "0" and press enter. That will hide ALL reminders as soon as they are completed.