Creation of safety level constraint throws exception

To reproduce:

- Open ACC example

- Switch to DSE perspective

- Import ACC project

- Open constraint editor

• Create a safety level constraint for any ECU

Expected behaviour:

• A safety level constraint is created

Obtained behaviour:

• The attached excpeption is thrown and no constraint is created

(from redmine: issue id 4022, created on 2020-05-14, closed on 2020-10-05)

• Uploads:
  • exception.txt