If one uses application variables for relationship names, then when filtering or searching for the relationship in the Workspace Properties you cannot search for the resolved variable. One is only able to see the application variable syntax. If the same format is used for many relationships, then it makes extremely inconvenient to find the correct relationship. Note: The behavior is opposite when filtering for relationship names in the model explorer.
Using TDM 188.8.131.52 On Windows 10 Enterprise Version 1809 OS build 17763.914.