The AfterOpen event occurs when a window opens. It occurs after the Microsoft Dynamics GP window open event.
window_AfterOpen()
• window – A window object.
Microsoft Dynamics GP uses the window open event to set default field values in the window, such as a default document date or a sort list selection.
Since the AfterOpen event occurs after the Microsoft Dynamics GP open event, use this event to override any default values that the accounting system sets for window fields.