src/vs/workbench/browser/parts/compositeBar.ts/CompositeBarModel/removeActivity
class CompositeBarModel:	removeActivity(id: string, activity: ICompositeActivity): boolean {
		const item = this.findItem(id);
		if (item) {
			const index = item.activity.indexOf(activity);
			if (index !== -1) {
				item.activity.splice(index, 1);
				this.updateActivity(id);
				return true;
			}
		}
		return false;
	}