src/vs/workbench/common/views.ts/ViewContainersRegistryImpl/deregisterViewContainer
class ViewContainersRegistryImpl:	deregisterViewContainer(viewContainer: ViewContainer): void {
		for (const viewContainerLocation of this.viewContainers.keys()) {
			const viewContainers = this.viewContainers.get(viewContainerLocation)!;
			const index = viewContainers?.indexOf(viewContainer);
			if (index !== -1) {
				viewContainers?.splice(index, 1);
				if (viewContainers.length === 0) {
					this.viewContainers.delete(viewContainerLocation);
				}
				this._onDidDeregister.fire({ viewContainer, viewContainerLocation });
				return;
			}
		}
	}