extensions/references-view/src/highlights.ts/EditorHighlights/constructor
class EditorHighlights:	constructor(private readonly _view: vscode.TreeView<T>, private readonly _delegate: SymbolItemEditorHighlights<T>) {
		this.disposables.push(
			vscode.workspace.onDidChangeTextDocument(e => this._ignore.add(e.document.uri.toString())),
			vscode.window.onDidChangeActiveTextEditor(() => _view.visible && this.update()),
			_view.onDidChangeVisibility(e => e.visible ? this._show() : this._hide()),
			_view.onDidChangeSelection(() => _view.visible && this.update())
		);
		this._show();
	}