Proper debugging in one form, vshost crash in another

Question

If I have a code problem in my main form, it debugs it fine (VS2008).  However, I have a selection on the form to call my separate form:

 private void preferencesToolStripMenuItem_Click(object sender, EventArgs e) {
  Form WSC = new WS_Config();
  WSC.ShowDialog();
  WSC.Close();
}


Any error on that WS_Config form causes vshost to crash rather than debug and show me the line with the problem.  Any ideas on why it does that?