A contextual tab is visible when a particular object in an app is selected. Contextual tabs cannot exist outside a contextual tab group, so we need to create a contextual tab group (RibbonContextualTabGroup) and bind a tab to this group. RibbonContextualTabGroup needs to be added to the Ribbon.ContextualGroups collection:
<!--Contextual Tab Groups-->
<Fluent:Ribbon.ContextualGroups>
<Fluent:RibbonContextualTabGroup x:Name="toolsGroup"
Header="Tools"
Visibility="Visible"
Background="Green"
BorderBrush="Green" />
</Fluent:Ribbon.ContextualGroups>
And associate a tab to this group:
<!--Contextual Tabs-->
<Fluent:RibbonTabItem Header="CT" Group="{Binding Source={x:Reference toolsGroup}}"/>
RibbonContextualTabGroup is not visible by default.
To show you must set RibbonContextualTabGroup.Visibility property to Visible.
To hide you must set RibbonContextualTabGroup.Visibility property to Collapsed.
Hidden is not supported a supported value for RibbonContextualTabGroup.Visibility.