A canvas which has a hidden form caching the events. contentsOfArea:into: uses the cache, instead of the main canvas. This is typically used with remote canvases, where querying the bits would involve a network transaction.

	initialization
	mainCanvas:

	canvas methods	top
	allocateForm:
	apply: evaluate aBlock with a canvas to do a drawing command on. See implementors for examples
	contentsOfArea:into: Return the contents of the given area
	form
	showAt:invalidRects:

	initialization	top
	mainCanvas:

	instance creation	top
	on: