This behavior is reproducible when we have applied Material theme and we have disabled the selection and drag of a RadTreeViewItem. 
A possible workaround is to set the MaterialAssist.CheckedBrush attached property to Null of the RadTreeViewItem which you don't want to select and drag.

 xmlns:material="clr-namespace:Telerik.Windows.Controls.MaterialControls;assembly=Telerik.Windows.Controls"

 <telerik:RadTreeViewItem Header="RootItem" material:MaterialAssist.CheckedBrush="{x:Null}" />

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.

The TreeView doesn't update the TriState of the parent item when an item is dragged and dropped.

In databound scenario the built-in checkbox and the tri-state mode are considered not supported and users are prompted to use checkbox in itemtemplate with 3state logic in the viewmodels.
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.

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.

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.
==================
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.

Dynamic change of the DataContext does not reflect the DataContext of the TreeViewItems.

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Adding a Checked RadTreeViewItem from code behind checks its parent which is xaml defined.
On loaded event of The RadTreeView adding a parent item and checked child item with Dispatcher.beginInvoke checks the parent.

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.


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1. End key does not work correctly when margin is set in the DataTemplate. Actually there is a small missmatch between the real "End" position and the one displayed by the tree.
2. When the IsAsynch property is used inside the binding of the ItemsSource property the End key does not work at all.

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.

This issue is applicable to Silverlight ONLY!

We have a RadTreeView with following properties IsLoadOnDemandEnabled="True", IsVirtualizing="True" and SelectionMode="Extended" set.
We select an element, collapse his parent and select another item. At this point if we expand the previously parent, both the newly selected item and the the first selected item are selected.
It is not correct the first item to preserve its selection state.

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.

CheckState of the RadTreeViewItem is lost when a child item is added programmatically in the Items Collection. When the Items collection is just rechanged ( Items  = new ObservableCollection<DataItem>) checkstate is NOT lost.

Please use CheckBoxes in DataTemplates.


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If virtualization is enabled, the RadTreeView resets the IsExpanded state of the root items to 'false' upon binding when child items are created.

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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 usgin PageDown key the final offset is different when using the End key. More over, the scroll event is fired several times when using the end key (3 in my case). Attached project reproduces the problem.

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.

There should be a way to exclude the partially checked items from the CheckedItems collection. 
A a property can be added to specify whether they will be included.

Edit: Please avoid using this collection because it ihas never been implemented completely in the 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.

When a checked item is programatically removed from the RadTreeView.Items collection, it isn't removed from the CheckedItems collection.

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.

We select a RadTreeViewItem by setting its property IsSelected to "True".
As a result, first "SelectionChanged" event is fired and second  - "Selected" event is fired.
If the selection is made "normally", by selecting an Item (with the keyboard or the mouse), the above events are fired in reversed order - first the "Selected" event and second the "SelectionChanged" evnet.

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.

TreeView: PreviewUnchecked doesn't stop unchecking of parent node when handled

If we have a TreeView with its "IsTriStateMode" property set to "True" and handle PreviewUnchecked event it is still possible to "uncheck" a root node.
The root node should have at least 2 successors and only one of them is checked. And the parent node is in "intermediate" (not checked/not unchecked) state. If we handle PreviewUncheck event, clicking of the parent node result in clearing (unchecking) of this node and all successors. This should not happen.
There is a sample project attached.

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 DataBound trees you can use the following approach =>  http://docs.telerik.com/devtools/wpf/controls/radtreeview/how-to/howto-tri-state-mvvm.html