WPF-925465-Added Note In Themes

Author: SatishRaj4377

wpf/Diagram/Themes.md

@@ -105,6 +105,8 @@ node.Annotations = new ObservableCollection<IAnnotation>()
 
 [View Sample in GitHub](https://github.com/SyncfusionExamples/WPF-Diagram-Examples/tree/master/Samples/Theme/ThemeStyle).
 
+N> When you apply a theme, it affects all [SfDiagram](https://help.syncfusion.com/cr/wpf/Syncfusion.UI.Xaml.Diagram.SfDiagram.html) elements and overrides any individual ShapeStyle settings for those elements. And also, you cannot update the `ShapeStyle` property for diagram elements when a theme is applied.
+
 ## See Also
 
 [How to apply built-in theme for node and connector?](https://support.syncfusion.com/kb/article/9995/how-to-apply-built-in-theme-for-node-and-connector-in-wpf-diagram-sfdiagram)