Since Refresh is the default choice of the Options menu
button, instead of opening the menu, you can simply click
on the Options button to refresh the view in the
window. Buttons in dstool have their first menu entry
as default choice.
You can clear both the view window and the trajectory points in memory
by clicking
in a view window canvas.
By holding and dragging ,
you can graphically
select a rectangle to evolve under the flow. See
Section 1.2.15 below for a complete description.