src/vs/workbench/browser/parts/sidebar/sidebarPart.ts/SidebarPart/doOpenViewlet
class SidebarPart:	private doOpenViewlet(id: string, focus?: boolean): Viewlet | undefined {
		if (this.blockOpeningViewlet) {
			return undefined; // Workaround against a potential race condition
		}

		// First check if sidebar is hidden and show if so
		if (!this.layoutService.isVisible(Parts.SIDEBAR_PART)) {
			try {
				this.blockOpeningViewlet = true;
				this.layoutService.setSideBarHidden(false);
			} finally {
				this.blockOpeningViewlet = false;
			}
		}

		return this.openComposite(id, focus) as Viewlet;
	}