From the Microsoft Dynamics GP Blogs: Voiding Historical Transactions; Command Forms; SOP Quote; Management Reporter Column Alignment

Microsoft Dynamics GP Voiding in Payables Management: Belinda Allen demonstrates this voiding process on her Belinda, the GP CSI blog. She details how to void historical transactions in a five minute video. She gives the example of voiding transactions that took place in April when the current month she's working in is May. She said a person has to void the payment first. The invoice will open once again, and then you can void the invoice. This is only part of Allen's explanation.  You can check out the full video:

Hidden Forms, Command Forms and Dictionary Context issues: These are quick tips from David Musgrave on the Developing for Dynamics GP blog. He first discusses Hidden Forms, saying at certain times this action is required.

He explains,

If you need a hidden form for your coding, rather than create a new one... use the one you probably already have. If you are integrating with the menu navigation of Microsoft Dynamics GP you will probably already have a Command Form set up with all your commands and menus for your application.  This form is opened on login and remains open at all times. So it is a perfect location to add a hidden window with your fields on it. Don't create new forms that you need to open and close, just use your existing Command Form.

He wraps up his post to explain Dictionary Context issues. He says, "Dictionary Context issues are when Dexterity executes code in the context of ...