I've known about this bug for some time. I had a go at fixing it when I first discovered it but Windows seems to be behaving oddly. If you look at the button it has a default button type border around it which means it should just work if you press Enter - but it doesn't. I haven't tried pressing Tab a few times until the button gets the focus but if that doesn't work too then something very odd is going on. I'll try and have another look at it later.

In case you are using MFC, you'll just need to name it "&Close" and it will automatically add underline under C character and therefore it's selectable with keyboard by pressing ALT+C.

- Kim