I agree-- directly clicking (right click, or shift + click) on a "to do" item to mark it complete would make this marvelous program almost perfect. Another solution would be to allow a hotkey assignment for "completed" or "dismissed" to do items.
I would also like to have completed items shown in strikeout, rather than shadowed. I tried editing the xml file, but when I put "strikeout" in formatting, the item just disappeared!
Final thoughts: would be nice to be able to set completed items to hide after 24 hours, or 1 day, or 1 week, etc. I like to remember what I have done for the day, and then start the next day fresh.
What a marvelous program. I love it's simplicity and integration with the desktop. Yippee.