/component superclass
 /PaintButton {
	% boolean --
	{BG2} {BG} ifelse
	setcolor 0 0 w h rectpath fill FG setcolor 0 [0 0
	w h] insetstroke aload pop rectpath stroke
} def

/Paint {
	% --
	false PaintButton
} def

/trackinpath false def

/trackbutton {
	% --
	trackx tracky pointinpath dup trackinpath
	ne {
		dup /trackinpath exch promote gsave
		newpath [exch] /PaintButton self Send
		grestore
	} {pop} ifelse
} def

/OnSelect {
	% --
	path /trackbutton track trackinpath {
		newpath /mouse_cancel ne {
			[false] /PaintButton self Send action
		} if
	} {pop} ifelse
	/trackinpath unpromote
} def