Watching Package global variable in debug session

I tried debugging an Oracle package with Oracle 17.
In watch part, it shows only local variables of procedure/function I am already in. Is there any way I can see global variables (defined in package body out of all functions/procedures)?

When I add a watch with name of global variable I get

ORA-06550: line 6, column 18:
PLS-00201: identifier 'PFI_ID' must be declared

By the way PL/SQL Developer has this feature