So I click on the Ubuntu main menu and go to Places>Pictures and Banshee opens. If I go to any of the files, Banshee opens (whether minimized or not). If I click on "Computer" or anything other than a folder, it works fine...
I'm not sure how to open a file in terminal or I could do that and give you the output.
I have no idea why it suddenly started doing this. I might try reinstalling Banshee.
I'm running 9.10 Karmic Koala right now.