Added KeyboardNavigationMode.Local.

src/Avalonia.Input/KeyboardNavigationMode.cs

@@ -36,5 +36,10 @@ namespace Avalonia.Input
         /// The container's children will not be focused when using the tab key.
         /// </summary>
         None,
+
+        /// <summary>
+        /// TabIndexes are considered on local subtree only inside this container
+        /// </summary>
+        Local,
     }
-}
+}

src/Avalonia.Input/Navigation/TabNavigation.cs

@@ -152,6 +152,9 @@ namespace Avalonia.Input.Navigation
             // Look for element with the same TabIndex before the current element
             while ((nextTabElement = GetPrevTabInGroup(nextTabElement, container, tabbingType)) != null)
             {
+                if (nextTabElement == container && tabbingType == KeyboardNavigationMode.Local)
+                    break;
+
                 // At this point nextTabElement is TabStop or TabGroup
                 // In case it is a TabStop only return the element
                 if (IsTabStop(nextTabElement) && !IsGroup(nextTabElement))