HyperNeWS requires a 'getanimated' type of tracking service.
The ClassTrackingCanvas tnt class provides these facillities. 
The routines below return the following track states:

/mouse_cancel:	There was no mouse down or the user cancelled, take no action.
/mouse_drag:	The mouse was dragged.
/mouse_up:	The mouse is up again, take action.
/mouse_click:	The mouse was clicked but not moved, take action.

subclasser routines
-------------------

A sub-class of ClassTrackingCanvas should define the following routines to
handle mouse down events:

/onselect		% --
	Select button was clicked

/onadjust		% --
	Adjustbutton was clicked

track routines
--------------

/trackable		% -- boolean
	Returns true if the currentprocess is allowed to call 'track'.

/track_state		% -- status
	Returns /mouse_click, /mouse_up, /mouse_drag or /mouse_cancel. 
	An allows the previewing of the mouse motion. For example: if 
	you click on the border of an X window you won't see a drag-rectangle
	until you move the mouse. Must be called before /track.

/track			% proc -- status
	Executes 'proc' repeatedly for every mouse move. When 'proc'
	is executed the event will be on the stack.
	Returns /mouse_click, /mouse_up or /mouse_cancel. The final
	position can be obtained with mousexy.

/track_overlay		% proc -- status
	Same as /track but an overlay is created first. erasepage is called
	when appropriate.

event management
----------------

/mouseevent		% -- event
	Return the last mouse event, or an nullevent if there wasn't one.

/eventxy		% event -- x y
	Return the x,y location of the event in the current coordinate system.

/mousexy		% -- x y
	Return the x,y location of the last mouseevent in the 
	current coordinate system.

/mouselevel		% -- n
	Return the click-level (double, triple click) of the last 
	mouse click.