title: `package-menu-mark-delete` doesn't mark selected package
body: <p>In <code>package-list-package</code>, I can't mark for deletion of installed package.</p>
  
  <p>I've tried with <kbd>d</kbd> and <code>package-menu-mark-delete</code> also, but no mark showed up.</p>
  
  <p>I can mark with <kbd>i</kbd> for install.</p>
  
  <p>How to find where is the problem?</p>