xkb: Switch delay to a group

[Ilya Murav'jov]

>> I have a list of ideas, of what could be part of a future XKB, and
>> switch-group-on-release is on there. I haven't had the canceling thing.
>> You want to cancel the group-switch if any unrelated key is being
>> pressed, right? Also, another modifier?
> Yes, you meant right, unrelated key/another modifier/whatever. But I've
> found out how to do it yet, the right way.

Oops, it's a typo. I've *not* found out yet.