Users can click the << button on the Selected Group header to collapse the navigation bar to a slender vertical strip that takes up less space in the area of the browser dedicated to your Silverlight application. When users want to interact with the navigation bar again, they can click the >> button to cause the Outlook®-style navigation bar to re-expand with all of its contents as it was before.

You can set the GroupsSource property of the Outlook®-style navigation bar to any enumerable collection as you would expect in any databound Silverlight control. Additionally, data templates can be specified that enable information to be extracted from your GroupsSource collection to be used in the group header and as group content. You can also declare groups in XAML or by modifying the Groups collection in code-behind.

When the Selected Group content needs a lot of space and/or there are many groups listed as buttons in the navigation group area, those groups at the bottom of the list automatically overflow to the overflow area at the bottom of the navigation bar. When more space becomes available, they are dynamically promoted up into the navigation group area again.

You can programmatically direct the xamWebOutlookBar™ to show more (or fewer) groups in the navigation area, and move groups up/down in the navigation area using the API similar to what users can do by using the Navigation Options Pane.

Like in Outlook®, the navigation bar has a horizontal thumb that separates the Selected Group area from the Navigation Area Groups presented below, and users can drag this thumb up or down to apportion more or less space to either area.