Cannot change property values in the console

On the current 12.0.0-SNAPSHOT it is not possible to change property values anymore. If you change the value the change should be detected and the "write changes to repository" button should turn red. This is not working anymore. I see no errors in the tomcat log or browser console log.

Adding a new property does still trigger the red button.

Note: the property field editor in the document type editor has the same problem. Change for example the caption on a field: the change is not shown. If you save the type then the changed caption is shown. This may be the same problem.