AND operator in CB Conditional

I try to show/hide a tab with "CB Conditional" settings.

If: value
Value: [cb:userdata field="my_field" AND field="my_field2" user="#me" /]
Is: empty
Then: hide

So I try to hide a tab when 2 of my OWN fields are empty. But that doesn't work. Is that the right way to use the "AND" operater in this case?

Thanks for your help!

Thanks a lot for this detailed post. I look ahead to article because my problem same with you. (Some little thing are different).