static S getText(final JTextComponent c) {
  ret c == null ? "" : (S) swingAndWait(func { c.getText() });
}

static S getText(final JLabel l) {
  ret l == null ? "" : (S) swingAndWait(func { l.getText() });
}

// returns the contents of text field for editable combo box
static S getText(final JComboBox cb) {
  if (isEditable(cb))
    ret str(cb.getSelectedItem());
  else
    ret unnull((S) cb.getEditor().getItem());
}