Concurrency problem when element is exported to Form while its space is opened

[tinchodias]

This can happen when a script in a Workspace creates an element in a space, sends show it it, and immediately sends inspect to the element.

The inspector preview tab for element defined in:

BlElement >>
inspectionPreview: aBuilder
	<inspectorPresentationOrder: 1 title: 'Preview'>

	^ aBuilder newMorph
		morph: self asPreviewMorph;
		yourself

ends up executing this:

BlElement >>
aeAsForm

    | invalidationBounds aCanvas |
    self isLayoutRequested ifTrue: [ self forceLayout ].

    "We want to consider our border, effect, as well as children's."
    invalidationBounds := self invalidationBoundsInSpace.
    aCanvas := AeCanvas extent: invalidationBounds extent.
    aCanvas pathTranslate: invalidationBounds origin negated.
    self aeFullDrawOn: aCanvas.
    ^ aCanvas asForm

This can be seen in this example of Toplo:

ToSandbox >>
example_SelectMaterialDesignIconMultiFiltrable

	| select   |
	select := ToMultiSelectElement new.
	self buildSelectListElementIn: select withIconProvider: ToMaterialDesignIconProvider.

	select filtrable: true.

	select nodeBuilder: [ :node :holder :iconDesc|
		| imPane |
		imPane := ToElement new layout: BlFrameLayout new.
		imPane fitContent.
		imPane withNullSkin.
		imPane background: Color veryLightGray.
		imPane addChild: (iconDesc icon size: 48 asPoint).
		node middleElement: imPane ].
	select fakeDataItem: select dataAccessor first.
	select hMatchParent.
	select placeholderText:
		('Select icons' asRopedText foreground: Color red).

	select inputTextField requestFocus.
	select openInSpace.
	select inspect

[tinchodias]

Related reading, in web/chrome:

-> A common performance issue in web apps is forced synchronous layout: reading the size of an element and forcing the browser to immediately and synchronously undergo layout and style calculations in order to figure out the size.
(https://tigeroakes.com/posts/resize-observer-avoid-forced-sync-layout/)

-> "Avoid forced synchronous layouts": https://web.dev/articles/avoid-large-complex-layouts-and-layout-thrashing#avoid_forced_synchronous_layouts