src/vs/workbench/browser/parts/sidebar/sidebarPart.ts/SidebarPart/create
class SidebarPart:	override create(parent: HTMLElement): void {
		this.element = parent;

		super.create(parent);

		const focusTracker = this._register(trackFocus(parent));
		this._register(focusTracker.onDidFocus(() => this.sideBarFocusContextKey.set(true)));
		this._register(focusTracker.onDidBlur(() => this.sideBarFocusContextKey.set(false)));
	}