Executing an Explain Plan causes CURRENT_SCHEMA to be erased. The following sequence will cause the CURRENT_SCHEMA to revert back the prior ALTER SESSION schema.
Log into the database with an Oracle 10g client and Execute the following statements in the Editor:
alter session set current_schema=SCOTT;
--Changes schema from originally logged schema
select sys_context('USERENV','current_schema') from dual;
--Displays schema as SCOTT
select 1 from dual;
-- Execute the Explain from the icon bar, see results
select sys_context('USERENV','current_schema') from dual;
--Shows schema as Original logged schema (original session_user, should still be SCOTT)