I received an email today from an account that has many customizations on their SalesLogix System.
During these customizations their business partner had removed many of the icons across the top of the screen, as well as a couple of items from the Navigation bar.
Because these items were removed early in the installation, even the Administrator who has only started working with SalesLogix recently, was unaware of functionality that is available out-of-the-box.
When you want to remove functionality from a Toolbar, a New toolbar should be created and released to the users that need it. Toolbars are layed one upon another. So, the original toolbar is always available for an Administrator to look it. This would prevent functionality being lost to everyone.
Leave the original Toolbar or Nav bar as it is. Good Business practice would be to Create a new Toolbar or Nav Bar and layer it on top of the existing.