<oPushButton>:select([<nInkeyValue>]) --> self

        <nInkeyValue> is a numeric value that indicates the key that
        triggered the push button's activation.  If passed, Select() waits
        for the key specified by <nInkeyValue> to be released before
        continuing.

        select() is a method of the PushButton class that is used for
        activating a push button.  When activated, a push button performs
        several operations.  First, select() sets SELF:BUFFER to true (.T.).
        Then, it calls SELF:display() to show the button in its highlighted
        color.  If <nInkeyValue> is passed, it waits for the key specified by
        <nInkeyValue> to be released.  Then, if present, it evaluates its
        sBlock code block.  select() then calls SELF:display() to show the
        button in its selected color.  A push button's state is typically
        changed when the space bar or enter key is pressed or the mouse's
        left button is pressed when its cursor is within the push button's
        screen region.

        This message is meaningful only when the PushButton object has input
        focus.