Clean unzip of V399w, open solution and build, no problems. I delete the MfgControl.AdvancedHMI.Controls.dll from the support folder in SolutionExplorer. Copy new dll to that folder and add back into project and Rebuild. I get errors and the Toolbox for the controls doesn't populate. I can replace the patched dll with the original (even just in WindowsExplorer) from the zip package, rebuild and all is well again.
My plan was to update to V399w and apply latest patches, it worked fine with Patch4 of the drivers.