extensions/references-view/src/tree.ts/SymbolsTree/constructor
class SymbolsTree:	constructor() {
		this._tree = vscode.window.createTreeView<unknown>(this.viewId, {
			treeDataProvider: this._provider,
			showCollapseAll: true,
			dragAndDropController: this._dnd
		});
		this._navigation = new Navigation(this._tree);
	}