RadGridView + VirtualQueryableCollectionView PageDown bug

[Gyula]

Dear Support!

I am using RadControls_for_WPF_2011_3_1205_DEV_hotfix.

When I am using RadGridView with VirtualQueryableCollectionView and I am pressing PageDown it's sometimes not working.
Every third keypress is not working (refer attachment).

Please let me know how to resolve the issue.

MainWindow.xaml

<Window x:Class="VirtualQueryableCollectionViewBugDemo.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        Title="MainWindow" Height="510" Width="700">
    <DockPanel>
        <TextBlock Width="250" Text="{Binding Log}" />
        <telerik:RadGridView ItemsSource="{Binding VirtualQueryableCollectionView}" EnableRowVirtualization="True" />
    </DockPanel>
</Window>

MainWindow.xaml.cs

namespace VirtualQueryableCollectionViewBugDemo
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            this.DataContext = new MainViewModel();
        }
    }
}

MainViewModel.cs

using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Linq;
using Telerik.Windows.Data;

namespace VirtualQueryableCollectionViewBugDemo
{
    public class MainViewModel : INotifyPropertyChanged
    {
        public VirtualQueryableCollectionView VirtualQueryableCollectionView { get; set; }
        private ObservableCollection<Row> items { get; set; }

        public MainViewModel()
        {
            this.items = new ObservableCollection<Row>(Generator.GenerateTestData());

            this.VirtualQueryableCollectionView = new VirtualQueryableCollectionView(this.items);
            this.VirtualQueryableCollectionView.LoadSize = 20;
            this.VirtualQueryableCollectionView.ItemsLoading += (s, e) =>
            {
                AppendLog(string.Format("Load StartIndex={0} ItemsCount={1}", e.StartIndex, e.ItemCount));
                this.VirtualQueryableCollectionView.Load(e.StartIndex,
                    this.items.Cast<Row>().Skip(e.StartIndex).Take(e.ItemCount));
            };
        }

        private string log;
        public string Log
        {
            get { return this.log; }
            set
            {
                this.log = value;
                RaisePropertyChanged("Log");
            }
        }
        public void AppendLog(string message)
        {
            this.Log = message + Environment.NewLine + this.Log;
        }

        public event PropertyChangedEventHandler PropertyChanged;
        private void RaisePropertyChanged(string propertyName)
        {
            if (this.PropertyChanged != null)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}

Model.cs

using System;
using System.Collections.Generic;

namespace VirtualQueryableCollectionViewBugDemo
{
    public class Row
    {
        public int Id { get; set; }
        public DateTime DateTime { get; set; }
        public TimeSpan TimeSpan { get; set; }
    }

    public static class Generator
    {
        public static int TestDataLength = 1 * 1000 * 1000;
        public static Random rng = new Random();

        public static List<Row> GenerateTestData()
        {
            var result = new List<Row>(TestDataLength);

            for (int i = 0; i < TestDataLength; i++)
            {
                string name = i.ToString();
                DateTime dateTime = new DateTime(rng.Next(1990, 2020), rng.Next(1, 12), rng.Next(1, 28));
                TimeSpan timeSpan = new TimeSpan(rng.Next(1, 23), rng.Next(1, 59), rng.Next(1, 59));

                result.Add(new Row()
                {
                    Id = i,
                    DateTime = dateTime,
                    TimeSpan = timeSpan
                });
            }

            return result;
        }
    }
}

[Vera]

Hello Balázs,

May I ask you to try our Latest Internal Build (December 12)? We have made some improvements and I believe that you will not experience any issues with the navigation.

Greetings,
Vera
the Telerik team