Please, help! A service in Safari doesn't perform as intended

I'm talking about "Send selection via e-mail" when you highlight some portion of text in Safari and want it to be send with Mail.app. When I click Send selected via e-mail the new message window opens but WITHOUT the selection, and what's strange is that I can't even close it. Only quitting Mail does close the window and I'm able to delete this blank draft only after relaunching Mail.

What's it all about? Is it a bug? How do I fix it?