title: Python - Dash input box is being reset even on `dash.no_update`
body: <p>I am creating a web interface based on Dash, where any client can control something on the server.<br />
  The web clients are updated regularly based on <code>dcc.Interval</code> callbacks, according to the server data.</p>
  <p>One input I need is a regular input box. The user could change the value or if the value is changed remotely the input box should be updated.</p>
  <p>But now I'm having the issue that the input box content is reset on each interval callback (even if it returns <code>dash.no_update</code>), making it impossible for the user to type something.</p>
  <p>In more detail, this is what happens in order in my code:</p>
  <ol>
  <li>New web client is opened</li>
  <li>Interval callback is triggered, which will update the content of the input box</li>
  <li>On further interval callbacks, the input box is unchanged as the remote value doesn't change (returns the <code>dash.no_update</code>)</li>
  <li>The user tries to type inside the input box</li>
  <li>On the next timed callback the input box content is reset to the last value</li>
  </ol>
  <p>Is there a way to prevent the input value from being touched at all by the timed callback, unless I want to?</p>
  <p>EDIT: I found out it's because I am using the <code>debounce</code> option for my <code>dcc.Input</code>. Without this option, the 'unsaved' content of the input is preserved during an update callback. But I do need that debounce feature, since I don't want to process half-entered values.</p>