Somehow, Expression Blend has entered full-screen mode (no window chrome), but I can still minimize/maximize/restore/move through the taskbar button. I don't see any menu options for full-screen mode, and the normal keyboard shortcuts don't work (F11, Alt-Enter).
I'm not sure how this happened, but I would sorely love to get my chrome back to make interacting with the window easier.
After not even trying to use Blend for my application for a really long time, it turns out it was my own fault to begin with. I had created a custom chrome control that would find its parent Window and remove the frame. I wasn't checking design mode, so whenever my control was instantiated by blend, it would remove all the chrome from the window :).