When in Design mode and trying to use an expression to set visibility on a constituent tab, you might notice that running as a user does not accurately reflect whether the user can actually see the tab.
We are currently evaluating this issue for a fix in a future service pack.
Steps to Duplicate
1. Go to a constituent record
2. Go into Design mode
3. Click Edit tabs at the top of the page
4. Select the tab and you want to secure
5. Edit the visibility expression to add the following expression: = (not Globals.CurrentAppUserName = "DOMAIN\[Username]") andalso (not Globals.CurrentAppUserName = "DOMAIN\[Username]")
6. In the CurrentAppUserName expression, change the term DOMAIN to your Domain, and [USERNAME] to the username of someone who shouldn't have access to the tab.
7. Notice that when you run as that user, you can see the tab but when they log in they cannot see the tab.