message: Fixed bug caught by unit test.
diff: @@ -579,7 +579,7 @@ export class HistoryTracker {
  stepsToUndo++;
  }
  - if (change.text === '\n' || change.text === '\r\n' || change.start.line !== currentLine) {
  + if (change.text.includes('\n') || change.start.line !== currentLine) {
  done = true;
  break;
  }
  