fixed #459

src/Shared/HandyControl_Shared/Controls/PropertyGrid/PropertyItemsControl.cs

@@ -2,8 +2,16 @@
 
 namespace HandyControl.Controls
 {
-    public class PropertyItemsControl : ItemsControl
+    public class PropertyItemsControl : ListBox
     {
         protected override bool IsItemItsOwnContainerOverride(object item) => item is PropertyItem;
+
+        public PropertyItemsControl()
+        {
+#if !NET40
+            VirtualizingPanel.SetIsVirtualizingWhenGrouping(this, true);
+            VirtualizingPanel.SetScrollUnit(this, ScrollUnit.Pixel);
+#endif
+        }
     }
 }