src/vs/platform/contextkey/browser/contextKeyService.ts/ScopedContextKeyService/dispose
class ScopedContextKeyService:	public dispose(): void {
		if (this._isDisposed) {
			return;
		}

		this._onDidChangeContext.dispose();
		this._parent.disposeContext(this._myContextId);
		this._parentChangeListener.dispose();
		this._domNode.removeAttribute(KEYBINDING_CONTEXT_ATTR);
		this._isDisposed = true;
	}