The following Options enabled --> Editor --> General's "Refresh OE after execution Create/Drop DDL" box unchecked,
Executing a script that altered an existing procedure (after checking that the procedure already exists).
Following successful execution of the script, a manual refresh of Object Explorer is performed.
Prior to the refresh, Object Explorer was displaying a list of all the Stored Procedures in the database.
After the refresh, the only entry under the "Stored Procedures" node was "SQL Server Database Error" next to a red and white "X" icon.