[DMN Designer] [BC Only] Unable to include DMN model

It is not possible to include DMN model.

Due to the Jira RHDM-1769  I tried to import DMN model. I was able to include the model (I could see it added in the Included Model tab) using RHDM 7.12.0 CR1 but when I pressed "Save" button I was able to see "Saving..." pop up message and nothing else. If I try to go to another project I get the message "You have unsaved changes in the... project, and they will be lost if you proceed. This action cannot be undone."