Defaulting DFF Context on Customer Site

Hi gurus,
I'm struggling with a DFF context.
On Customer page I have JG_HZ_CUST_ACCOUNTS DFF that has a defaulting context set to null, which is fine.
On Customer Site page there's JG_HZ_CUST_ACCT_SITES DFF defaulting with a value (case is "Italian Permanent Establishment Information"). This context has mandatory and mostly unused fields. This situation is causing a huge time loss each time a user actibity cross this page because of everytime context value have to be set to null before whatever next action is going to be taken.

I tried to set context  default to a value that is not requiring mandatory fields but page seems not considering my change.