If there are many tables with a column of the same name, then if we do not explicitly choose a table, any modifications made could be ambiguous.
For example, If there is a table with columns actor_id and actor, and another table with film_name and actor_id, a stored procedure with join on both tables will result in a column actor_id. While updating the column, it could pertain to either the film table or the actor table.
Therefore, the only way to edit a result where multiple tables are involved is by selecting a specific table from the drop down and editing the values in that table.