With Dynamics CRM 2011, there are many ways to get the same task done when you are customizing your solution.  However, what prefix is used depends on where you came from.  Let’s take the scenario of creating an entity.  If you are working in the Default Solution, then you probably have a prefix of new_ unless you have already changed the prefix of the Default Publisher:

If you are working in a solution you’ve created, but using the Default Publisher, then you probably still have a new_ prefix.  If you are working in a solution you’ve created, using a publisher you’ve created, and created the new entity in from within that solution, then you will have the prefix of the publisher you created:

However, when you customize anything through the Customize tab in the ribbon:

…you will be brought to the Default Solution, which means your prefix will be whatever is in the Default Publisher.  To get your prefix to show up when you use the Customize tab, you need to update the prefix of the Default publisher to match the prefix of your publisher:

By doing so, your prefix will be the default everywhere you try to customize the system.

@devkeydet