* #include <ul_pbar_graphics:xygraph.h>
* TXYGraph__Result XYGraph__DisplayCoordinates( void )
* Function intent:
* XYGraph__DisplayCoordinates() processes the cursor tracking of X-Y
* coordinates in the plot window. XYGraph__DisplayCoordinates() must be
* called at a regular rate (typically within pgm_per()) to be responsive to
* the user's actions.
* Function parameters:
* Function return value:
* CBS_OK success
* CBS_NOSETUP XYGraph__DisplayGraph() has not been called or...
* XYGraph__EnableCoordinates() not been called
* else wn_xxx() function error occured