src/vs/workbench/browser/parts/activitybar/activitybarPart.ts/ActivitybarPart/onDidChangeViewContainerVisibility
class ActivitybarPart:	private onDidChangeViewContainerVisibility(id: string, visible: boolean) {
		if (visible) {
			// Activate view container action on opening of a view container
			this.onDidViewContainerVisible(id);
		} else {
			// Deactivate view container action on close
			this.compositeBar.deactivateComposite(id);
		}
	}