Dynamics 365 - enable a custom entity to appear in the regarding lookup

Question

When I create a task, I'd like to set a record of a custom entity as "Regarding". The solution explained here does not work. Any suggestions?

Answer 1

You have to complete all these steps:

1. An entity must be Activities enabled for it to appear in the Regarding lookup. Enable a custom entity to appear in the Regarding lookup.

2. An entity must also be enabled for Unified Interface for it to appear in the Regarding lookup. Read more.

3. Open the App designer, Add > Entities and then select the entity you want to add and complete the addition by including all assets. Reference