SharePoint 2010 Ribbon for Developers

Overview: SP2010 implements the ribbon UI. Ribbon in the same as word 2007 ribbons in that it provides contextual actions that the user can use. This post looks at styling and controlling/extending the ribbons functionality.
Notes:

• Ribbon is styled using corev4.css, this changes depending on if you apply a theme. css styling starts with "ms-cui" in the css.
• SPD can add custom actions.
• Ribbon is controlled by SP file 14\Template\global\xml\CMDUI.xml, this is merged with our custom xml file at run-time to result in an extended ribbon displayed to users.
• Deploy the custom ribbon xml using a feature.
• Buttons can be easily added or existing buttons replaced or hidden using XML declaratively to include custom ribbon actions.
• Ribbon can also be modified programmatically (SPUserCustomAction)