I just discover something on the Edit Tab functions.

As Administrator, you can allow or not allow user to change the Edit tab.

If you allow, user can change the hide tabs and also rearrange their own tabs even you already set the which edit tab need to be hide.

If you dont allow, user can not change the hide tabs or rearrange it. To disallow user to change, log-in as administrator then click the Admin link. In the Admin page, click on Configure tab. In the configure tab, you can set the edit tab for global usages and uncheck the option "Allow all users to configure tabs". Then in the User Management page, click on each user profile to hide and arrange the tab. With this, user do not have the options to rearrange or hide tabs.

Have fun trying it. This is a good features...Please correct me ,if i am wrong,,,Have a nice day.