Fred,

>After upgrading my DevExpress XtraEditors controls to version 6.2.6, I am no longer able to open any existing DevExpress form containing an XtraTabControl (NullReferenceException). Neither can I instantiate a new XtraTabControl on a new DevExpress form.
>
>Removing MM.NET DevExpress controls resolves the problem.
>
>I did not check every XtraEditors control in the toolbar but the rest of the controls appeared to be working.

That's because the MM .NET DevExpress assemblies are compiled with the previous version of DevExpress. We are in the process of releasing the new version of our subclasses, but for now, you can do the following:

1. Open the MM .NET DevExpress project
2. Remove references to the old DevExpress assemblies
3. Add referencdes to the new DevExpress assemblies back in
4. Add your own strong key file to the DevExpress project (if you don't know how to do this, see the MM .NET Dev Guide topic "Recompiling MM .NET Assemblies" for details.
5. Recompile the project.

Best Regards,