Limit access to MES customization

I've customized a couple of buttons on the MES production tab.  I set the security id in Sub Process Maintenance to a specific ID that limits access to a select few.  I was hoping that doing that would allow the users in the security id to load the customized version and if the user wasn't in that id then the uncustomized form would load.

That almost happens, but if the user isn't authorized I get an error saying "Can not load the customized version of the MES Menu for the Process ID UDMES1.  Verify the Process ID specified in the mfgsys file is valid."  If I click on the "Ok" button in the message box then the regular MES form loads, which is what I wanted, minus the error message.  If the user is in the security id list, everything works as expected.

So, my question is, can I somehow suppress the error message for non-authorized users, or am I trying to do something that can't be done this way?  If it can't be done this way, is there a better way to load the customized form for some users and the standard form for everyone else?

BTW, using Vantage 8.03.410