An Extender window is attached to a transaction entry window. When the transaction is posted the data disappears from the Extender window.
In the Extender window setup, click on the Options button. In the Options window, make sure you do not have a “Table Link” setup on the window. Adding a table link to transactional type records will cause the data to be removed when the document is posted.
Microsoft Dynamics GP generally uses 3 tables for each transaction type, a work table, open table, and history table. As you post a document, it will move from the work table to the open table. Once the document is fully paid it moves the document to the history table. What causes the record delete issue is that when the document is moved from table to table, it’s DELETED from the previous table. The deletion of the record from the previous table will delete the Extender data if there is a table link established on that table.
Table Links should only be used on master records and not transactional records. An example of a master record would be a customer, vendor, item, site, account number, etc… When you delete a master record, you typically want the Extender data to delete also.