The Unquote - Android Studio common attributes: adjustViewBounds does not exist

The cumul.Project 5 has this hint for Android Studio ConstraintLayout for the project:
Under the Common Attributes Panel , ImageView provides an attribute named adjustViewBounds . Setting adjustViewBounds to true will cause the ImageView to maintain the original aspect ratio of its content.

The problem is, that in the common attributes panel I only see min and max for height and width + alpha, nothing else. If I add this adjustViewBounds int the search field, it does not exist.

Does it matter though? The view seems ok.

I noticed that sometimes the view refreshes slowly and sometimes you have to come off and on again to make the changes needed. Suddenly I found the right view. But I have other problems arisen, too.