Hello Abs,

Thank you for following up. Please add your styles to your Node and Connection definitions each time you perform a load from the PersistenceManager.

eg.

private void LoadButtonOnClick(object sender, RoutedEventArgs e)
        {
            using (IsolatedStorageFile file = IsolatedStorageFile.GetStore(IsolatedStorageScope.User | IsolatedStorageScope.Domain | IsolatedStorageScope.Assembly, null, null))
            {
                if (file.FileExists(DiagramFileName))
                {
                    using (IsolatedStorageFileStream stream = new IsolatedStorageFileStream(DiagramFileName, FileMode.OpenOrCreate, file))
                    {
                        PersistenceManager.Load(EmployesDiagram, stream);
                        Style nodeStyle = this.Resources["EmpNode"] as Style;
                        Style connectionStyle = this.Resources["EmpNodeConnection"] as Style;
                        EmployesDiagram.ConnectionDefinitions[0].ConnectionStyle = connectionStyle;
                        EmployesDiagram.NodeDefinitions[0].NodeStyle = nodeStyle;
                       
                    }
                }
            }
        }

For more details, I've modified your sample and I have attached it to this thread below. Let me know if you have any questions.

Thank Michael for the advice, I have followed it, however it did not work. Can you please take a look at the attachment and see what is missing from here?