title: Cannot save page settings in TYPO3 7.3 (yellow warning sign)
body: <p>Since yesterday, a very weird behaviour happens to be introduced to my TYPO3 instance. The yellow warning sign is displayed beneath the "Resources" tab in page settings preventing me from saving any changes. But it's not displaying beneath any field that could be the problem. I can't seem to remember having changed anything in the template's TS setup. Please tell me if you need any more information.</p>
  
  <p><a href="https://i.stack.imgur.com/SEW1Y.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SEW1Y.png" alt="Screenshot of problematic view"></a></p>