My tabbed app does not redisplay the view with an orientation change.
I added
android:configChanges=\"keyboardHidden|orientation\"
In Mono for Android with a target API greater then 13 I found that the line which would go inside the namespace but outside the Activity class:
[Activity (Label = "Viewer", ConfigurationChanges = ConfigChanges.Orientation|ConfigChanges.ScreenSize)]
lead to the triggering of OnConfigurationChanged() even though changing the manifest had not.