Double delete in Mail

I'm using Apple's Mail app on my Mac Pro and lately I have to delete everything twice from my trash folder. If I'm in my inbox and delete a message it goes to the trash folder as it should. Same for junk mail. But when I go to empty the trash folder I have to delete it twice. When I try to delete it the first time it doesn't go away until I do it the second time. Anyone else having this problem?

TIA