Introduction
Along with the Fluent UI definition come the ribbon tabs, the quick access toolbar and the status bar. Read more about the Fluent UI in the Fluent UI Concepts.

In Creo Elements/Direct Modeling there exist two different instances of a ribbon: one for base modeler along with all applications and modules and one which is explicitely available in Creo Elements/Direct Annotation. This means that for Creo Elements/Direct Annotation the ribbon tabs, quick access toolbar and status bar must be defined in parallel to everything which is done for Creo Elements/Direct Modeling and the other applications and modules. It also means that for any creation of a ribbon element it must be specified, in which of the two ribbon instances it should be created.

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It is not possible to create an additional ribbon instance. But it is possible to create additional ribbon tabs and change the visibility of existing ribbon tabs in certain applications.

When switching between different applications the visibility of ribbon tabs is changed according to the specification in the ribbon tab definition. Nothing needs to be done programmatically.

To define the contents of a ribbon tab available commands need to be defined. Read more about the concept of available commands. Every control action is defined via a single available command. The command definition comes along with a title label, description, icon and enable status. All these informations are used to define a ribbon control but can be overwritten. This way for instance a label can be changed compared to the existing title in the available command.
It is also possible to directly specify an action when defining a ribbon control. This mechanism could be used for testing purposes but should not be used for writing add-on functionality. Every available command can be used for customization of ribbon controls. If a ribbon control action is specified directly in the ribbon control definition a customization is not possible.

Note: To make use of the available commands the available commands files must be loaded before the ribbon contents are defined. Otherwise the available commands are unknown and the control action will be empty. Read more on loading customization files here.

Example: A detailed example for a ribbon tab definition can be found in file fluent_ui_lsp.html.