in src/highlights.ts [21:29]
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();
}