20
I am not sure why the limitation on the WebClient exist but I suggest removing this limitation in the WebClient and making Lookup in the Lists possible like in RTC.

Example: User cannot Lookup on Customer No. or Vendor No. in the Contact List.

Source:
https://docs.microsoft.com/en-us/dynamics-nav/feature-limitations-of-the-microsoft-dynamics-nav-web-client
Look for C/AL Triggers
Category: Sales
STATUS DETAILS
Completed
Ideas Administrator

Good news! We released this feature as part of the functionality in Show and go to related records from a list.

Please refer to the following link for more information:
 
Best regards,
Blazej Kotelko
Program Manager, Microsoft