message: Don't try to set line number on disposed python shell
diff: @@ -365,7 +365,7 @@ private void TraceCallback(TraceBackFrame frame, string result, object payload)
  private void SetLineNumber(int lineNum)
  {
  - if (recurse || me == null || me.scriptEditor == null)
  + if (recurse || me == null || me.IsDisposed || me.scriptEditor == null)
  return;
  recurse = true;
  