XmTrackingEvent provides a modal interface for selection of a
component.
It is intended to support context help.
The function grabs the pointer and discards succeeding events until
BSelect is released or a key is pressed and then released.
The function then returns the widget or gadget that contains the
pointer when BSelect is released or a key is released.
widget
Specifies the widget ID of a widget to use as the basis of the modal
interaction. That is, the widget within which the interaction must
occur, usually a top level shell.
cursor
Specifies the cursor to be used for the pointer during the interaction.
This is a standard X cursor name.
confine_to
Specifies whether or not the cursor should be confined to widget.
event_return
Returns the ButtonRelease or KeyRelease event that causes the function
to return.
Return value
Returns the widget or gadget that contains the pointer when BSelect
is released or a key is released. If no widget or gadget contains the
pointer, the function returns NULL.