src/vs/workbench/services/progress/browser/progressIndicator.ts/EditorProgressIndicator/registerListeners
class EditorProgressIndicator:	private registerListeners() {

		// Stop any running progress when the active editor changes or
		// the group becomes empty.
		// In contrast to the composite progress indicator, we do not
		// track active editor progress and replay it later (yet).
		this._register(this.group.onDidModelChange(e => {
			if (
				e.kind === GroupModelChangeKind.EDITOR_ACTIVE ||
				(e.kind === GroupModelChangeKind.EDITOR_CLOSE && this.group.isEmpty)
			) {
				this.progressBar.stop().hide();
			}
		}));
	}