CheckedItems collection of RadTreeView contains all items.

Edit: Please avoid using this collection because it has never been implemented completely in RadTreeView. In DataBinding scenarios, you can use CheckBox in the ItemTemplate of the RadTreeView. Approach can be found here =>
http://docs.telerik.com/devtools/wpf/controls/radtreeview/how-to/howto-tri-state-mvvm.html 
CheckedItems colelction can be implemented in the ViewModels, instead of using the built-in property.

The XAML team has recently reviewed this issue and will not be addressing it as at this time the team is focusing on the bugs impacting the highest number of developers. If you have encountered this issue and it is blocking for your work please contact us through the support ticketing system with details on your setup and a reference to this item.

Multiple operations applied on a big RadBitmap can cause OutOfMemoryException because of used and not disposed unmanaged resources in a WriteableBitmap object.

Steps to reproduce:
- Execute multiple times the Rotate tool
Observe: The memory goes up and retains such.
Expected: The unmanaged memory is cleared.

Findings: the memory leak is related to the WPF class WriteableBitmap which is internally used by the RadBitmap. Attached is a sample project illustrating the problem using only WPF classes.
Note: At this point, we are not aware of a possible fix.

Scrollbar scrolls unexpectedly when column width is changed. Check the following video for a reference:
http://screencast.com/t/Y6IwtREc

A memory leak related to the automation peers of the RadPane and RadPaneGroup appears when you close a pane (using its Close button) even if you call its RemoveFromParent() method.

To work this around disable the automation peers. To do so please set the static AutomationManager.AutomationMode property toAutomationMode.Disabled.

The issue originates from ItemsControlAutomationPeer. It is reported to Microsoft in their old connect portal here =>

https://connect.microsoft.com/VisualStudio/feedback/details/838165/memory-leak-in-the-itemscontrolautomationpeer-because-items-removed-from-the-itemscollection-are-still-strongly-held-by-the-weakrefelementproxystorage

Setting transparent background to RadBookItem doesn't work properly.

Placeholder is set to " " and the SelectionOnFocus is set to CaretOnBeggining. When the Mask receives the focus, the caret is under the MouseClick position, not in beggining.
After load and clicking in the center of the MaskedInput , no value can be inserted.

The xaml team recently reviewed the status of this issue and won't be addressing it in future. 
Placeholder set to string.empty or ' ' should be considered not supported. Please consider using Mask="" (no-mask) instead.

Place a RadComboBox in the GridViewColumn header and set SelectedIndex in the xaml. The SelectionChanged event is fired, but the command is not executed.

As a workaround you can set the SelectedIndex in xaml instead of on the Loaded event,

TreeView: When the header of an Item is set to a TextBox, the selection of a RadTreeViewItem is incorrect

The original reported issue is that the following style does not work as expected.
<Style TargetType="telerik:RadTreeViewItem">
<Style.Triggers>
<Trigger Property="IsKeyboardFocusWithin" Value="True">
<Setter Property="IsSelected" Value="True" />
<Setter Property="Tag" Value="Selected" />
</Trigger>
<Trigger Property="IsKeyboardFocusWithin" Value="False">
<Setter Property="IsSelected" Value="False" />
<Setter Property="Tag" Value="Unselected" />
</Trigger>
</Style.Triggers>
</Style>

This is not supported by the RadTreeView Selection logic. Once the trigger applies with Selected / True, the IsSelected property is Locally set via the selector's code. This means future work of the trigger will not be successful over the IsSelected Property.
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The XAML team has recently reviewed this issue and will not be addressing it as at this time the team is focusing on the bugs impacting the highest number of developers. If you have encountered this issue and it is blocking for your work please contact us through the support ticketing system with details on your setup and a reference to this item.

Tree is Virtualized and bind to colelction of DataItems.
On a button click, we add new Dataitem with IsInEditMode = true (bound to IsInEditMode of the RadTreeViewItem).
The new Item is in edit mode but the textBox in the ItemEditTemplate has no DataContext so no actual editing  can be performed.

Scenario casn be solved with adding the item, then switch its editmode in dispatcher:
DataItem item = new DataItem() { Name = "Item Editable" };
             
            (this.tree.ItemsSource as ObservableCollection<DataItem>).Insert(0, item);

            Dispatcher.BeginInvoke(new Action(() =>
            {
                item.IsInEditMode = true;
            }), DispatcherPriority.Loaded);

The XAML team has recently reviewed this issue and will not be addressing it as at this time the team is focusing on the bugs impacting the highest number of developers. If you have encountered this issue and it is blocking for your work please contact us through the support ticketing system with details on your setup and a reference to this item.

When the slider is placed inside a ScrollViewer and the scrollviewer is resized fast a "Layout cycle exception is thrown".

The original scenario where we reproduce the exception is the following:
SelectionStart, SelectionEnd, Minimum and Maximum of the Slider are bound to DateTime.Ticks via converter.
Exception is not reproduced if you move the Mininum declaration in xaml before the Maximum. And same for SelectionStart = before SelectionEnd.

We are closing this item due to the workaround and the fact that it is NOT reproducible in WPF.

If your scenario is different, please open a new support thread with more information regarding this exception.

When click with mouse on the text it is selected every second time even when SelectionOnFocus is set to "SelectAll". If you click before the text it is selected every time.

When a checked item is loading on demand its check state is lost.
This issue is applicable for both WPF and Silverlight.
And the issue is present always (no matter if the RadTreeView is databound, virtualized, etc).

Edit: Please use the approach from this help article if you need checkboxes in the RadTreeView.
http://docs.telerik.com/devtools/wpf/controls/radtreeview/how-to/howto-tri-state-mvvm.html

The XAML team has recently reviewed this issue and will not be addressing it as at this time the team is focusing on the bugs impacting the highest number of developers. If you have encountered this issue and it is blocking for your work please contact us through the support ticketing system with details on your setup and a reference to this item.

When TreeView is databound to RadObservableCollection and Suspen/Resume Notifications are used when removing items the Selected items collection contains empty object at the end after deleting item and selecting another one.

As a workaround you can use ObservableCollection.


The XAML team has recently reviewed this issue and will not be addressing it as at this time the team is focusing on the bugs impacting the highest number of developers. If you have encountered this issue and it is blocking for your work please contact us through the support ticketing system with details on your setup and a reference to this item.

In a two monitors scenario the ApplicationMenu appears on the left monitor when the RibbonView with negative left margin is hosted in a RibbonWindow which is maximized on the right monitor.

EDIT:
We are closing this issue as the described behavior as expected. When logged first, the negative left margin of RibbonView was not taken into account.
When popup opens and its parent starts on the left monitor, popup calculates that it cannot fit entirely and changes its direction of opening. This expected by the WPF Framework.
When you give negative left margin of the RibbonView, its application button might also goes with 1-2 (or more) pixels on the left monitor. Then popup (the application menu opens in a popup) has no space and changes its opening direction to left.
This is expected and the only reasonable solution would be changing the negative left margin to positive or 0.