FirstDown, OtherDown,
FirstUp or LastUp.
The blank area in the window
that catches the mouse events
is created by a subtype of LeafVBT.
A LeafVBT is so primitive that it does not even redraw itself.
So we override the repaint method with one that does the repainting.
In this case there is nothing important to do,
just fill in with the background color.
The mouse events are caught by supplying our own mouse method
which does much more than the default mouse method
(which does nothing).
Our mouse method, called MouseEvent is in
Event.m3.
It receives a data structure called MouseRec.
The method extracts the various pieces of the structure and
displays them in the appropriate text fields of the main application.
Two views of the application while it is running are show in:
Mouse 1
Mouse 2