src/vs/base/browser/ui/tree/abstractTree.ts/TreeRenderer/disposeElement
class TreeRenderer:	disposeElement(node: ITreeNode<T, TFilterData>, index: number, templateData: ITreeListTemplateData<TTemplateData>, height: number | undefined): void {
		templateData.indentGuidesDisposable.dispose();

		if (this.renderer.disposeElement) {
			this.renderer.disposeElement(node, index, templateData.templateData, height);
		}

		if (typeof height === 'number') {
			this.renderedNodes.delete(node);
			this.renderedElements.delete(node.element);
		}
	}