src/vs/workbench/services/views/browser/viewDescriptorService.ts/ViewDescriptorService/onDidChangeDefaultContainer
class ViewDescriptorService:	private onDidChangeDefaultContainer(views: IViewDescriptor[], from: ViewContainer, to: ViewContainer): void {
		const viewsToMove = views.filter(view =>
			!this.viewDescriptorsCustomLocations.has(view.id) // Move views which are not already moved
			|| (!this.viewContainers.includes(from) && this.viewDescriptorsCustomLocations.get(view.id) === from.id) // Move views which are moved from a removed container
		);
		if (viewsToMove.length) {
			this.moveViewsWithoutSaving(viewsToMove, from, to);
		}
	}