The windows titlebar is missing so so I can't drag the window around. There's still a thin border around the whole thing so I can drag to resize in any direction (including up) but no titlebar. I've always had one until now, but it's suddenly gone.
It's possibly related to MarkdownPad 2. I just installed that a little while ago and it required installing some .net stuff. I wonder if there is some incompatibility.