If item is expanded from the UI and viewport is scrolled to the top calling BringIndexIntoView causes the viewport to lock while scrolling.

Available in LIB version: 2016.2.516 

TreeView is in TabItem of TabControl with IsContentPreserved = False. On ContextMenu open and when working with Contextmenu, the underlying RadTreeViewItem is in MouseOverState. Changing tabs then back to the tab with the TreeView. When working with contextmenu, the underlying treeviewitem is not is mouseoverstate. Could be reproduced in CustomContextMenu QSF sample. Not reproducible in AddRemoveDisable sample.
The workaround is to set IsContentPreserved to true on the RadTabControl.

In a virtualized TreeView, after ExpandAll and scroll operations, there are gaps in the TreeViewPanel.

The children count is read incorrectly by MS Narrator

RadTreeViewItem.AutomationProperties.Name is not read correctly since version 2011.2

Setting the IsChecked via binding causes synchronization issue with CheckState during initial container creation.

Declined.

IsChecked and CheckState are not supported in binding scenarios. In databinding scenarios use the approach described here.
http://www.telerik.com/help/wpf/radtreeview-howto-tri-state-mvvm.html

Add 'None' to the selection mode enum

Modify the SelectionChanged event logic so that the event is only fired once - exposing both the RemovedItems and AddedItems collections.

If RadTreeView.IsEnabled  false (or the tree is inside busy BusyIndicator), then ExpandItemByPath(or GetItemByPath) does not work.

Available in LIB version: 2016.2.525

The TreeViewPanel doesn't display the TreeViewItems when the TreeView ItemsPresenter ControlTemplate element is wrapped in a Border or Grid control.

Declined.

Changing the default control template of our controls is risky, every template part has its purpose and usually it is used in code behind. 
We cannot support such template changes to not reflect the main features such as virtualization,scrolling, fast performance.

Ability to have both static and bound RadTreeViewItems or different hierarchy levels.

Reason for decline: There is no proper way this to be implemented.
 This would require huge refactoring of the DragDrop, Styling, Editing, Virtualization logic. 
Complexity of such task  is close to writing a new control from scratch.

In databinding scenarios, the Header is somehow not stretched when setting the HeaderContentAlignment to true

Collapse a RadTreeViewItem when all its children are dragged elsewhere. This is needed in scenarios where the RadTreeViewItem DefaultImageSrc and ExpandedImageSrc properties are set, and you want to revert back to the DefaultImageSrc once all children of the item are dragged to other positions.

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

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.

Change the selection on MouseLeftButtonUp instead of MouseLeftButtonDown.

DataTriggers that apply DefaultImageSrc, ExpandedImageSrc don't work when the TreeView is virtualized.
Reason for deletion:
The workaround is easy - just bind the DefaultImageSrc, ExpandedImageSrc to string properties from the ViewModel.
Also, a possible fix would slow down the virtualization process in the RadTreeView.

If the TreeView SelectionMode is Extended, dragging a single selected item while holding the Ctrl key will deselect the item

Available in Q1 2015

Improve the synchronization between the TreeView.IsOptionElementsEnabled with the TreeViewItem.OptionType property. In a scenario where the TreeViewItem.OptionType property is databound, changing the TreeView.IsOptionElementsEnabled property doesn't respect the databound values of the TreeViewItem.OptionType.
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Reason for deletion: These  proeprties are marked obsolete.

When TreeView is placed inside floating VS ToolWindow and item is selected the visual state remains unchanged after focus leaves the TreeView.

Reordering checked items using the drag/drop implementation in a TreeView with IsTriStateMode=False, sets the parent item in an indetereminate state