% mark { p killprocess } stopped cleartomark

/MakeXCanvas { % can => -
  dup == beep
  /NewMagic ClassXPieWindow send
  /new ClassEventMgr send /activate 2 index send
  /w exch def
} def

/i createevent def

i /Name /MapNotify put
i /Priority 100 put

{ i expressinterest
  { awaitevent
      /Canvas get
      [   exch
	  {   dup null eq { pop exit } if
	      dup /Parent get
	  } loop
      ]
      dup length 4 ne { pop } {
          1 get
	  dup /ParentDictArray known { pop } {
	      MakeXCanvas
	  } ifelse
      } ifelse
  } loop
} fork
/p exch def
p ==