How to reproduce: check the attached project:

Workaround: when the form is opened in the designer make sure that all pages are made visible at least ones so the controls are initialized, before attempting to access collection editors via properties window

Currently the pages are wrapped around, i.e. when one reaches the last pages and select next using the down arrow key the first page gets selected

Workaround: 
Public Class MyRadPageView
    Inherits RadPageView

    Public Overrides Property ThemeClassName As String
        Get
            Return GetType(RadPageView).FullName
        End Get
        Set(value As String)
            MyBase.ThemeClassName = value
        End Set
    End Property

    Protected Overrides Function CreateUI() As RadPageViewElement
        Select Case Me.ViewMode
            Case PageViewMode.Stack
                Return New RadPageViewStackElement()
            Case PageViewMode.Outlook
                Return New RadPageViewOutlookElement()
            Case PageViewMode.ExplorerBar
                Return New RadPageViewExplorerBarElement()
            Case PageViewMode.Backstage
                Return New MyRadPageViewBackstageElement()
            Case Else
                Return New RadPageViewStripElement()
        End Select
    End Function

End Class

Public Class MyRadPageViewBackstageElement
    Inherits RadPageViewBackstageElement

    Protected Overrides ReadOnly Property ThemeEffectiveType() As Type
        Get
            Return GetType(RadPageViewBackstageElement)
        End Get
    End Property

    Protected Overrides Function SelectNextItemCore(current As RadPageViewItem, forward As Boolean, wrap As Boolean) As Boolean
        Return MyBase.SelectNextItemCore(current, forward, False)
    End Function

    Protected Overrides Sub ProcessKeyDown(e As KeyEventArgs)
        If Me.IsNextKey(e.KeyCode) AndAlso Not Me.IsEditing Then
            Me.SelectNextItem()
        ElseIf Me.IsPreviousKey(e.KeyCode) AndAlso Not Me.IsEditing Then
            Me.SelectPreviousItem()
        ElseIf e.KeyCode = Keys.Home AndAlso Not Me.IsEditing Then
            Me.Owner.SelectedPage = Nothing
            Me.SetSelectedItem(Me.Items.First())
        ElseIf e.KeyCode = Keys.End AndAlso Not Me.IsEditing Then
            Me.Owner.SelectedPage = Nothing
            Me.SetSelectedItem(Me.Items.Last())
        ElseIf e.KeyCode = Keys.F2 Then
            BeginEdit()
        ElseIf e.KeyCode = Keys.Escape Then
            CancelEdit()
        ElseIf e.KeyCode = Keys.Enter AndAlso Me.IsEditing AndAlso Me.ActiveEditor.Validate() Then
            EndEdit()
        End If
    End Sub

End Class

To reproduce: use the following code snippet:

public RadForm1()
{
    InitializeComponent();

    this.radPageView1.Pages.Add(new RadPageViewPage("My page"));
    RadPageViewStripElement stripElement = this.radPageView1.ViewElement as RadPageViewStripElement;
    stripElement.StripButtons = StripViewButtons.ItemList;

    this.radPageView1.ItemListMenuDisplaying += radPageView1_ItemListMenuDisplaying;
}

private void radPageView1_ItemListMenuDisplaying(object sender, RadPageViewMenuDisplayingEventArgs e)
{
    e.Items.Clear();
    RadMenuItem item = new RadMenuItem("aaa");
    e.Items.Add(item);
}


Click the overflow button to open the drop down and select the item. When you open the overflow popup again you will notice that the item is duplicated although you clear the items in the ItemListMenuDisplaying event.

Workaround: dispose the item when it is clicked

private void radPageView1_ItemListMenuDisplaying(object sender, RadPageViewMenuDisplayingEventArgs e)
{
    e.Items.Clear();
    RadMenuItem item = new RadMenuItem("aaa");
    item.Click += item_Click;
    e.Items.Add(item);
}

private void item_Click(object sender, EventArgs e)
{
    RadMenuItem item = sender as RadMenuItem;
    if (item != null)
    {
        item.Click -= item_Click;
        item.Dispose();
    }
}

To reproduce: 

for (int i = 0; i < 20; i++)
{
    this.radPageView1.Pages.Add(new RadPageViewPage("Page" + i));
}

this.radPageView1.ViewMode = PageViewMode.Backstage;

Only a few of the pages are visible and the user is not allowed to scroll to see the rest of them.

Workaround: 
1. Make use of the strip buttons:

            RadPageViewBackstageElement el = this.radPageView1.ViewElement as RadPageViewBackstageElement;
            el.ItemContainer.ButtonsPanel.Visibility = ElementVisibility.Visible; 

2. Place the control in RadScrollablePanel

 RadScrollablePanel scrollablePanel = new RadScrollablePanel();
            scrollablePanel.Dock =  DockStyle.Fill;
            this.Controls.Add(scrollablePanel);

            RadPageView pageView = new RadPageView();
            pageView.ViewMode = PageViewMode.Backstage;
            scrollablePanel.Controls.Add(pageView);

            for (int i = 0; i < 50; i++)
            {
                pageView.Pages.Add(new RadPageViewPage("Page " + i.ToString()));
            }

            
            pageView.Size = new System.Drawing.Size(1000,2500);

To reproduce:

1. Add a RadPageView with several pages.
2. Disabled some of the pages.
3. When running the application, try to navigate through pages with the arrow keys. You will notice that the disabled pages are also selected.

Workaround: 

public class CustomPageView : RadPageView
{
    public override string ThemeClassName  
    { 
        get 
        { 
            return typeof(RadPageView).FullName;  
        }
    }

    protected override RadPageViewElement CreateUI()
    {
        if (this.ViewMode == PageViewMode.Strip)
        {
            return new CustomViewElement();
        }
        return base.CreateUI();
    }
}

public class CustomViewElement : RadPageViewStripElement
{
    protected override Type ThemeEffectiveType     
    { 
        get    
        { 
            return typeof(RadPageViewStripElement);     
        }
    }

    protected override bool CanSelectItem(RadPageViewItem item)
    {
        bool result= base.CanSelectItem(item);
        return result && item.Enabled;
    }
}

To reproduce:
- Add a RadPageView with several pages to a form.
- View the tabs by setting the SelectedTab property.
- Create a form instance and show it with the ShowDialog method.
- Select the second tab.
- Reopen the form and select a tab after the second. You will notice that the content is not changed.
 
Workaround:
Create a new instance each time when the form is shown.

To reproduce: 
1. Drag and drop RadPageView on the form
2. Select the control and open a smart tag 
3. You will see that the 'Dock in parent container' option is not added 

Hello,
PageView with Windows8 Theme, ViewMode Stack, Stack Position Left
Tabs are drawn incorrectly, see attachment.
can i work around this issue?
Thanks

Workaround: instead of removing and adding the page, modify its Visibility property

To reproduce:
- Add RadPageView change the view  to ExplorerBar and add some pages with controls.
- Start the application expand all pages and scroll.

Workaround:
class MyPageView : RadPageView
{
    protected override RadPageViewElement CreateUI()
    {
        if (this.ViewMode == PageViewMode.ExplorerBar)
        {
            return new MyExplorerBarElement();
        }
        return base.CreateUI();
    }
   
}

class MyExplorerBarElement : RadPageViewExplorerBarElement
{
    protected override bool IsChildElementExternal(Telerik.WinControls.RadElement element)
    {
        return !(element is RadPageViewElementBase) && base.IsChildElementExternal(element);
    }
    protected override Type ThemeEffectiveType
    {
        get
        {
            return typeof(RadPageViewExplorerBarElement);
        }
    }
}

To reproduce:
- Add RadpageView to a form and build the application.
- Merge the assemblies with .NET Reactor
- Run the new exe file.

To reproduce:
- Add PageView to a form and set its Dock property to fill.
- Add single page and set its AutoScroll property to true.
- Add some controls and make sure that a scrollbar will appear.
- Start the application and scroll to the bottom.
- Maximize the form. You will notice that the scrollbar position is wrong.

 Workaround:
protected override void WndProc(ref Message m)
{
    if (m.Msg == 0x0112) 
    {
        if (m.WParam == new IntPtr(0xF030)) 
        {           
            this.radPageView1.SelectedPage.AutoScrollPosition = this.radPageView1.AutoScrollPosition;
        }
    }
    base.WndProc(ref m);
}

Workaround:
            RadPageViewExplorerBarElement exElement = radPageView2.ViewElement as RadPageViewExplorerBarElement;
            exElement.ItemSize = new Size(200, 100);
            

To reproduce:
1. Add a RadPageView with no pages and set its Dock property to Fill.
2. Set the ViewMode property to ExplorerBar at design time.
3. Use the following code snippet:

private void AddOutputPage(int index)
{
    string title = "Test-Page " + index;
    RadPageViewPage page = new RadPageViewPage(title);
    this.radPageView1.Pages.Add(page); 
}

private void Form1_Load(object sender, EventArgs e)
{
    for (int i = 0; i < 20; ++i)
        AddOutputPage(i);
}

As a result the current page header at the top of the RadPageView is not displayed until you resize the pageview.

Workaround:
public Form1()
{
    InitializeComponent();
    this.radPageView1.RightToLeft = System.Windows.Forms.RightToLeft.Yes;
}

public class CustomPageView : RadPageView
{
    public override string ThemeClassName  
    { 
        get 
        { 
            return typeof(RadPageView).FullName;  
        }
    }

    protected override RadPageViewElement CreateUI()
    {
        switch (this.ViewMode)
        {
            case PageViewMode.Strip:
                return new CustomRadPageViewStripElement();
            
            default:
                return base.CreateUI();
        }
    }
}

public class CustomRadPageViewStripElement : RadPageViewStripElement 
{
    public CustomRadPageViewStripElement()
    {
    }

    protected override Type ThemeEffectiveType     
    { 
        get    
        { 
            return typeof(RadPageViewStripElement);     
        }
    }

    protected override bool IsNextKey(Keys key)
    {
        if (this.RightToLeft)
        {
            if (key == Keys.Left)
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        return base.IsNextKey(key);
    }

    protected override bool IsPreviousKey(Keys key)
    {
        if (this.RightToLeft)
        {
            if (key == Keys.Right)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        return base.IsPreviousKey(key);
    }
}