    <kbd class="compound">
          <kbd>S</kbd>+<kbd class="move">Move keys</kbd>
        </kbd>
      </td>
      <td>Subtract rectangular area from selection</td>
    </tr>
    <tr>
      <td>
        <kbd>A</kbd>
      </td>
      <td>Select the whole level (mark all)</td>
    </tr>
    <tr>
      <td>
        <kbd>U</kbd><span class="asterisk">*</span> or <kbd>X</kbd>
      </td>
      <td>
        Clear selection<br>(unmark all)
        <p>
          <span class="asterisk">*</span>
          Except f