getMyField().requestFocus()

public static void activateTabAndRequestFocus(IFormField field) {
  selectTab(field);
  field.requestFocus();
}

/**
 * Recursively set tab as selected in all GroupBoxes to display the field.
 *
 * @param field
 */
private static void selectTab(IFormField field) {
  ICompositeField f = field.getParentField();
  IGroupBox selectedGroupBox = null;
  while (f != null && !(f instanceof ITabBox)) {
    if (f instanceof IGroupBox) {
      selectedGroupBox = (IGroupBox) f;
    }
    f = f.getParentField();
  }
  if (f != null) {
    if (selectedGroupBox != null) {
      ((ITabBox) f).setSelectedTab(selectedGroupBox);
    }
    selectTab(f);
  }
}

  @Override
  public void activateProblemLocation() {
    //make sure the table is showing (activate parent tabs)
    IGroupBox g = m_field.getParentGroupBox();
    while (g != null) {
      if (g.getParentField() instanceof ITabBox) {
        ITabBox t = (ITabBox) g.getParentField();
        if (t.getSelectedTab() != g) {
          t.setSelectedTab(g);
        }
      }
      g = g.getParentGroupBox();
    }
    m_field.requestFocus();
  }