If I open the About window by clicking Help->About, I can close it again by clicking inside the window.
This is probably by design, but I think it’s unintuitive; in other programs, this is seldom the way windows function, especially about windows. I don’t think it’s a good idea.
Also, it would be good to make the text in the about window selectable; I just tried to copy the version number out of the window, but I couldn’t.