Fix for #118 where move notification is duplicated.

src/ObservableCollections/SynchronizedViewList.cs

@@ -190,8 +190,8 @@ private void Parent_ViewChanged(in SynchronizedViewChangedEventArgs<T, TView> e)
                         var oldIndex = listView.RemoveAt(e.OldStartingIndex);
                         var newIndex = listView.Insert(e.NewStartingIndex, e.NewItem.View);
                         OnCollectionChanged(e.WithNewAndOldStartingIndex(newStartingIndex: newIndex, oldStartingIndex: oldIndex));
+                        return;
                     }
-                    break;
                 case NotifyCollectionChangedAction.Reset: // Clear or drastic changes
                     listView.Clear(IterateFilteredIndexedViewsOfParent()); // clear and fill refresh
                     break;

tests/ObservableCollections.Tests/ToNotifyCollectionChangedTest.cs

@@ -1,3 +1,5 @@
+using System.Collections.Specialized;
+using System.Diagnostics;
 using ObservableCollections;
 
 namespace ObservableCollections.Tests;
@@ -56,4 +58,25 @@ public void ToNotifyCollectionChanged_Filter()
         e.Current.Should().Be("$4");
         e.MoveNext().Should().BeFalse();
     }
-}
+
+    [Fact]
+    public void ToNotifyCollectionChanged_Move()
+    {
+        var list = new ObservableList<int> { 0, 1, 2, 3 };
+
+        var view = list.CreateView(i => i)
+            .ToNotifyCollectionChanged();
+
+        int moveEventCount = 0;
+
+        view.CollectionChanged += (_, e) =>
+        {
+            if (e.Action == NotifyCollectionChangedAction.Move)
+                moveEventCount++;
+        };
+
+        list.Move(0, 1);
+
+        moveEventCount.Should().Be(1);
+    }
+}