2008/11/7 Bert Freudenberg <bert at freudenbergs.de>:
>
> On 07.11.2008, at 01:35, Igor Stasenko wrote:
>
>> Now, second thing, if you look through code, how PasteUpMorph works
>> with Display, it acquring an #assuredCanvas , which in own turn
>> makes sure it gets new, fresh __offscreen__ form , having same
>> dimensions as current Display to draw into it.
>
>
> World assuredCanvas form == Display
>

Hi Bert,

hmm, if you look at

WorldState>>assuredCanvas
	remoteServer ifNotNil:[^self assuredRemoteCanvas].
	(canvas isNil or: [(canvas extent ~= viewBox extent) or: [canvas form
depth ~= Display depth]])
		ifTrue:
			["allocate a new offscreen canvas the size of the window"
			self canvas: (Display defaultCanvasClass extent: viewBox extent)].
	^ self canvas

the line:

Display defaultCanvasClass extent: viewBox extent

creates a new form if current canvas is nil. And its not a
DisplayScreen class instance, its a Form.
Now i can't find a code, which restoring canvas if it was reset, back
to use canvas which having form == Display.

Aha... reading Andreas reply i found the place where canvas is set
back to Display canvas..
Its in #doDeferredUpdatingFor:

> - Bert -

-- 
Best regards,
Igor Stasenko AKA sig.