PROCEDURE MouseEvent(v:MouseVBT; READONLY cd: VBT.MouseRec) =
    VAR
        point:=cd.cp.pt;
        mods:=cd.modifiers;
        text:="";
    BEGIN
        CASE cd.whatChanged OF
        | Modifier.MouseL => TextVBT.Put(v.whatChanged, "Left Button");
        | Modifier.MouseM => TextVBT.Put(v.whatChanged, "Middle Button");
        | Modifier.MouseR => TextVBT.Put(v.whatChanged, "Right Button");
        END;
        TextVBT.Put(v.time, Fmt.Unsigned(cd.time)); (* really Word.T *)
        TextVBT.Put(v.cp, "("&Fmt.Int(point.h)&","&Fmt.Int(point.v)&")");
        IF (Modifier.Shift   IN mods) THEN text := text&"+Shift";   END;
        IF (Modifier.Lock    IN mods) THEN text := text&"+Lock";    END;
        IF (Modifier.Control IN mods) THEN text := text&"+Control"; END;
        IF (Modifier.Option  IN mods) THEN text := text&"+Option";  END;
        TextVBT.Put(v.modifiers, text);
        CASE cd.clickType OF
        | ClickType.FirstDown => TextVBT.Put(v.clickType, "FirstDown");
        | ClickType.OtherDown => TextVBT.Put(v.clickType, "OtherDown");
        | ClickType.OtherUp   => TextVBT.Put(v.clickType, "OtherUp");
        | ClickType.LastUp    => TextVBT.Put(v.clickType, "LastUp");
        END;
        TextVBT.Put(v.clickCount, Fmt.Int(cd.clickCount));
    END MouseEvent;