Key press = default button?

[SkylyJay]

Sorry if this is explained somewhere else, but I was unable to find it.

I have a few windows, I'd like to change slightly, and for the most part, I have it figured out. One thing I cant find the details for, is how some custom windows, have a key press, activate the default button of the top most window. Such as some tradeskill windows, having the enter key able to activate the create, repeat, stop buttons.

If someone would explain how to set that up, I would apreciate it.