Selections: add a dynamic dropdown in compound causes NPE in included doc type (patch attached)

Pre-requisites:
There is an existing compound - contentblocklocation - and an existing document type - locationdocument - which has this compound property. There is a document - location1 - of this document type.

Action:
Add a new MANDATORY Dynamic-dropdown in the compound - contentblocklocation - and configure it to refer on some valuelist

Result in the CMS:
Opening the document type - locationdocument - that contains the compound will cause a stacktrace on screen and logfile. Opening the document -location1 - will cause NPE on screen and logfile

Result in the Console:
the prototype of the document type - locationdocument - will not have a property for the added mandatory dropdown in the compound. The compound will have the prototype initialized properly