A QuickBtnVBT.T is a button that activates immediately on down-clicks. Quick buttons are useful for boolean toggles and radio buttons.
A QuickBtnVBT has its pre, action, and post methods called on every mouse click of type FirstDown in its domain. Its cancel method is never called. Its default pre and post methods are no-ops.
INTERFACE QuickBtnVBT; IMPORT ButtonVBT, VBT; TYPE T <: ButtonVBT.T;
The call v.init(ch, action, ref) initializes v as a quick button with child ch and action procedure action, and adds ref to v's property set if it is not NIL.
PROCEDURE New( ch: VBT.T; action: ButtonVBT.Proc; ref: REFANY := NIL): T; <* LL.sup = VBT.mu *>
END QuickBtnVBT.
New(...) is equivalent to NEW(T).init(...).