message: Add null check for lineDiv
diff: @@ -3104,7 +3104,7 @@ export class Cursor {
  public onLine(pos: number) {
  const lineDiv = this.lineDiv();
  - return (pos >= lineDiv.linePos) && (pos < lineDiv.lineEnd);
  + return lineDiv && (pos >= lineDiv.linePos) && (pos < lineDiv.lineEnd);
  }
  public lineDiv() {
  