Let us take incident form as an example.
1. Remove 'Additional comments' from the form layout.
2. Set the 'sys_user_preference' of 'glide.ui.incident.stream_input' for testSNC user to 'comments'.
3. Log in as the testSNC user.
4. Open an incident record.
The Work notes is not available on the form while the post button is still on the Activity formatter.
This behavior has been recorded as problem PRB1238364 which has been fixed in London release.
The workaround is to delete that sys_user_prefernce ''glide.ui.table_name.stream_input'' record or update it to 'work notes'.
However, if we set sys_user_preference 'glide.ui.activity_stream.multiple_inputs' to true for the user, this issue will not happen.
It will put both Addition comments and Work notes on the Activity Formatter. The sys_user_prefernce 'glide.ui.table_name.stream_input' will not take effect anymore.