Technote Details :: Synchronize tables
Issue
When trying to edit an older query, some of the table fields are marked with a red cut-through line.

Reason
This happens because some of the table columns used in the initial query no longer exist in the database. highlights these by placing a red mark on the columns it can't find. These columns cannot be used in the query anymore.
Solution
There are two solutions to this issue:
Alter the tables, and add the missing columns. When you re-open with the same stored query, the columns will be usable again.
Right-click on the table that displays the missing columns and select Synchronize. This will update the displayed query tables by removing the columns. On save, the query will be updated.