Happened again. Opened Construct from the start menu, as usual, not as an administrator (even though I've got the preview server set up for the local network, I usually don't bother with it) and after hitting the save button in the upper left corner, and then hitting the red X in the upper right, my project closed, but Construct did not.
Pretty sure I wasn't tabbing between programs or anything weird like that when I opened it. Windows 7, 64-bit.
Again, alt-F4 crashes the program. This isn't a big deal for me, but if I can help get the bug fixed, I'd like to.
So far I've always had to have the program open for a while; I haven't been able to cause it by launching, opening a project, and quitting again.