How do you configure what buttons a user in a given role can add/remove on their button bar?

Summary:

How do you configure what buttons a user in a given role can add/remove on their button bar?

Content (required):

How do you configure what buttons a user in a given role can add/remove on their button bar? We know users can click the gear wheel to add/remove buttons, but how do you configure the choices they have in the button list? For example, making the "Send Password" button available when viewing employee records.

Version (include the version you are using, if applicable):

TBE

Code Snippet (add any code snippets that support your topic, if applicable):