If you define a RadMaskedInput control in the ItemEditTemplate of RadTreeView and then bind the Value property of the masked input to a property from the RadTreeViewItem's view model, the input displays the view model's class ToString() method. Instead the value of the bound property should be displayed.

Fix is available in LIB Version: 2015.3.1005.

BringIntoView and GetItemByPath are slow on trees with many nested levels (20-30).
In Q2 2014 these methods will be faster in scenarios with TreeView Lines.

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 

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

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

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.

When the FlowDirection is RightToLeft, the vertical lines of the control aren't properly aligned.

The issue is not reproducible with R3 2016 Release.

Update the radtreeview-howto-exapand-select-item-with-lod-enabled-treeview

It was suggested that the ItemTemplates in the tree view should update when the item template selector or the item template is changed.

This will be hard to implement properly because of the numerous ways in which a template can be set. A naive implementation is more doable, though we are not notified when the ItemTemplate property changes
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Reason for marking this Declined: Too little information, too old item (5.5 years) with too litle votes.

The request is related to the method AddItemByPath - To build the whole hierarchy not only to add the string after last separator.

Too specific requirement that could be implemented as application logic.

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.

Programmatically reorder items with animation.

Declined. This could be implemented as application logic. The requirement is too specific to be included in the publi API of the RadTreeView.

Allow selecting and unselecting items on right click when the SelectionMode is Multiple/Extended.

Reason for decline: This can easily be implemented as application logc using th MouseRightButtonDown event of the RadTreeView.

Dynamically change of the theme of the RadTreeViewItems cannot be achieved.

Reason for decline:
The bug is outdated. Every RadTreeViewItem can be Styled via its Style property or the ItemContainerStyle of the RadTreeView.

Expose properties that controls the lines color and their thickness like in the RadTreeListView.

When expanding all items with a horizontal scrollbar the last item is hidden by the scrollbar. As a workaround, you can set the IsVirtualizing property of the RadTreeView to True.

When you reorder the collection very fast an exception is thrown. This is reproducible when the UI virtualization is enabled with its virtualization mode set to Recycling, and an item is selected. Also, you can observe some missing items glitches instead of the exception. To reproduce this you can call the ObservableCollection's Move() method several times in a single method (see the attached project). 

In this case also a NullReferenceException is thrown sometimes instead of the InvalidOperationException.

To work this around delay the reordering calls so that the treeview has time to properly measure and arrange itself. For example:

Items.Move(10, 2);
Application.Current.Dispatcher.BeginInvoke(new Action(() =>
{
Items.Move(10, 2);
}), System.Windows.Threading.DispatcherPriority.Background);

Select an item with mouse, scroll thousands of items down and then shift select item to perform range selection. This will block the UI thread for seconds. 

Selection is not updated when using the arrow keys if the current selected item is outside the viewport.

Select nested item in virtualized treeview with single selection mode.

Collapse its parent. Select item in the level of the parent. Expand the parent and notice two items are visually selected.

Expexted : only the last selected item with mouse should be visually selected.

Workaround:

private void TreeView_ItemPrepared(object sender, RadTreeViewItemPreparedEventArgs e)
{
    if ((e.PreparedItem.IsSelected == true && this.TreeView.SelectedItem != null && this.TreeView.SelectedItem != e.PreparedItem.Item))
        e.PreparedItem.IsSelected = false;
}