Error "ORA-02019: connection description for remote database not found" when running a DBLink que (4305961)

When running a simple DBLink query such as 'select * from dual@dblinkname', using execute statement (F9),  the following error occurs:

"ORA-02019: connection description for remote database not found"

This only happens if I run the query using Execute Statement (F9). It runs successfully using Execute as script (F5), Execute in SQL*Plus, and Execute in QSR.

A default schema had been set in the Toad Options and the 'Used in' set to 'ALL' ie.

'View | Toad Options | Oracle | General | Default Schema | Used in' to ALL

This has the effect of setting an ALTER SESSION SET CURRENT_SCHEMA=[new schema] for the editor session and this schema does not own the DBLINK.

Set 'View | Toad Options | Oracle | General | Default Schema | Used in'  to 'Schema Browser' only (this is the default).