Adding Command to Ribbon button

Our Ribbon is designed to work just like a regular WPF Menu and Toolbar. Basically if you have a CommandTarget assigned to a button, it will operate directly on that element and its enabled state will related to that element as well. If no CommandTarget is used (which is the case most of the time), the command searches for a handler at or "above" the currently focused element in the main focus scope. So if you move focus outside of the main focus scope where there is no handler for a command, it will disable. This is standard WPF command processing behavior, and I'm sure you can find a lot more info on it by searching the MSDN.