The symptom of this bug is that as soon as the issue occurs, the user is no longer able to tab between fields in any Microsoft Dynamics GP window.
The nature of the bug is a combination of a .NET Framework application window (typically a Dynamics GP Add-in) displayed as a modal window and having VBA active in Dynamics. After the Add-in window is closed, the issue prevents the user from being able to tab between fields in any Microsoft Dynamics GP window until they exit Microsoft Dynamics GP.
The reason for the Microsoft.Dexterity.Support.FilterEvents.dll is to resolve MBS Great Plains bug 46619 in all versions of Microsoft Dynamics GP 10.0.