VBA Run Time Errors Not Reported Visio 2010

[paulv45]

I first reported something along these lines yesterday under the subject:
VBA Untrapped Error Handling 2007/2010 Differences
but now am realizing that what I am seeing is more insidious that differences.
What I am experiencing is that if there is an error during the execution of a Ribbon OnAction operation it never gets reported to the user.
I'm guessing that GetEnabled etc. would exhibit the same behavior but have not yet checked.
So it would seem that OnError handling is critical to make sure the user knows what is going on.
Are others encountering this or is it something I have done?
Thanks.
Paul