</A></H3>
This command implements simple pointer and keyboard grabs for Tk.
Tk's grabs are different than the grabs
described in the Xlib documentation.
When a grab is set for a particular window, Tk restricts all pointer
events to the grab window and its descendants in Tk's window hierarchy.
Whenever the pointer is within the grab window's subtree, the pointer
will behave exactly the same as if there had been no grab at all
and all events will be reported in the normal fashion.
When the pointer is outside 