How to add the user's group next to his display name in the activity

[Alon Grod]

Hi,

Im trying to add the user's group name next to his display name in the activity inside incident's form. I know that the sys_history_line table stores all relevant data when an action is taken on the incident. I tried to write onAfter Business rule that will change the user_name (type string) to the '123' (just for testing) and its not working, But when I go to the sys history line and change the user_name to '123' manually, it also changes in the activity. Why the BR is not working and when I changed manually its working?

Before changing Manually (My display name is being displayed after changing state):

sys_history_line table with the upadate (BR does not work):

changing value  manually in sys_history table (user_name = '123'):

Incident activity ('123' is being shown):

 

 
This is the BR that its not working (I tried to do both on before and on after):

 

[Prince Arora]

@Alon Grod 

I am not sure how you have updated the fields of sys_history_line 
actually table is read only for me in my PDI, check below:

[Alon Grod]

@Prince Arora i changed the ACL in order to have the option to change these fields and when I changed it manually i can see its affecting the incident's activity but when im trying to change using a BR its not affecting