or
private void recalculateFirstAndLastVisibleIndexes() { var gvvp = this.radGridView.ChildrenOfType<GridViewVirtualizingPanel>().FirstOrDefault(); if (gvvp == null) return; var rowsList = gvvp.ChildrenOfType<GridViewRow>(); if (rowsList.Any()) { int firstIndex = this.radGridView.Items.IndexOf(rowsList.ElementAt(0).Item); foreach (var row in rowsList) { firstIndex = Math.Min(firstIndex, this.radGridView.Items.IndexOf(row.Item)); } FirstVisibleRowIndex = firstIndex; NumOfVisibleRows = rowsList.Count(); } else { FirstVisibleRowIndex = 0; NumOfVisibleRows = 0; } } recalculateFirstAndLastVisibleIndexes function.

Hello, I have got Window with modalWindow.
I face issue.
When I am opening the modal window and after clicking on iconApp on taskbar, modal window is disappears and I can't do anything with my app (only end app in task manager). See attached files
<t:RadWindow xmlns:n="clr-namespace:Telerik.Windows.Controls.Navigation;assembly=Telerik.Windows.Controls.Navigation" n:RadWindowInteropHelper.ShowInTaskbar="True" x:Class="SOme.Some.MainWindow" t:StyleManager.Theme="Metro" MinHeight="480" MinWidth="800" Height="650" Width="1024" WindowStartupLocation="CenterScreen" xmlns:vm="clr-namespace:someName">.....</t:RadWindow>var mainWindow = new MainWindow();mainWindow.Show();<t:RadWindow x:Class="Some.Some.SomeWindow" t:StyleManager.Theme="Metro" WindowStartupLocation="CenterScreen" CanMove="False" CanClose="False" ResizeMode="NoResize" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"> ...</t:RadWindow>var mainWindow = new NewClientWindow();mainWindow.ShowDialog();xmlns:n="clr-namespace:Telerik.Windows.Controls.Navigation;assembly=Telerik.Windows.Controls.Navigation" n:RadWindowInteropHelper.ShowInTaskbar="True"