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The bug is outdated.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.

Setting the HeaderStringFormat of RadTreeViewItem does not format the Header.

As a workaround, HeaderTemplate of RadTreeViewItem could be set which has TextBlock with StringFormat property set on its Text Binding.



 <DataTemplate x:Key="template">
                <TextBlock Text="{Binding ., StringFormat='Received ({0:N0})'}" />
</DataTemplate>


Available in LIB version: 2016.3.1121

Generated item cache is not cleared properly. This leads to memory leaking when items are virtualized and realized. 

As a workaround you can set the IsVisualCacheEnabled property of the TreeViewPanel to False. Note that this will work only in Recycling VirtualizationMode.

<telerik:RadTreeView.ItemsPanel>
    <ItemsPanelTemplate>
        <telerik:TreeViewPanel IsVisualCacheEnabled="False" />
    </ItemsPanelTemplate>
</telerik:RadTreeView.ItemsPanel>

Virtualized RadTreeView.

Windows Display Size is set to Larger (150%).

Expanding and collapsing TreeViewItems leads to ArgumentException in TreeViewPanel.ExtendDesiredSize method - "Width and Height must be non negative".

Available in LIB version: 2015.3.1207 

If the  RadTreeView control is used on touch device in scenario with Checkbox support, the TreeViewItem  cannot be (un)checked with a single tap.  

Available in LIB version: 2015.3.1109

Selecting an item via tap does not work when ScrollViewer.PanningMode has a value other than None.

TreeView is bound to CollectionViewSource. Certain items are expanded. The CVS is refreshed leading to ArgumentOutOfRange Exception in the TreeViewPanel.cs

NOTE: The bug is reported via the following scenario. When the bound IsExpanded property is changed in the model, OnCollectionChanged with NotifyChangedCollectionAction.Reset is invoked.

We consider this as highly unsafe operation. What actually happens is that by the time containers are measured / arranged (because the IsExpanded is triggered) - Reset also triggers reset / measure arrange of all items. This is the same as modifying a list/collection when it is iterated - the framework wll throw an error.

To better prove this is unsafe, we also tested System.Windows.Controls.TreeView. On MouseDown, we set IsExpanded = true on collased item and in the PropertyChnaged handler we invoked OnCollectionChanged with Reset in the bound ObservableCollection. This resulted in StackOverflowException in PresentationCore.dll.

Conclusions. The Exception is fixed in the RadTreeView but we consider invoking Reset in such moment (during measure/arrange) as not supported / critical / unsafe operation.

When switching to a different window, the selected item in the RadTreeView stays in a selected in-focus state. The expected behavior is not to be focused any more (turn gray).

TreeView is in dropdowncontent of a DropDownButton. BringPathIntoView is called on loaded of the button (or the tree). It tries to bring several nested levels deep for example item 90.3.2.1 (4 levels deep).
On opening the button , the scrollviewer is not scrolled to the desired item.

Posssible workarounds:

 - invoke the BringPathIntoView method in a Dispatcher.BeginInvoke call

 - disable the treeview animations before the call and enable them after the call ( telerik:AnimationManager.IsAnimationEnabled = False)

The children of an expanded RadTreeViewItem dropped inside another item are not indented correctly. 

This behavior is observed in the Office2016 theme.

Dear Telerik team,
We currently have a problem with the RadDragAndDropManager as we are currently in the process of converting from Silverlight to WPF.
We are also converting Telerik from version 2011.2 to the current version of Telerik WPF.
Now the following error happens:
If I drag an item and drag it over another dropable area, the DragCue element moves.
The error occurs as soon as "e.QueryResult" is set to true in the OnDropQuery function.
You just have to do that, otherwise the drop will not be evaluated.

I was able to recreate the whole thing in a new project with just a RadTreeView and a RadMap.
I just don't want to switch the RadDragAndDropManager to the DragDropManager because we have a lot of our own controls that run with the old one, but not with the new one.
I've already tried that, but the conversion effort is just too big.
Can you see why the DragCue element is acting so weird?

With best regards

Markus Kuhlemann

RadTreeView is throwing an IndexOutOfRangeException when the host panel is resized. 
StackTrace:
 at Telerik.Windows.Controls.TreeView.IndexTree.CumulativeValue(Int32 endIndex) in c:\TB\105\WPF_Scrum\Release_WPF\Sources\Development\Controls\Navigation\TreeView\Virtualization\IndexTree.cs:line 271
   at Telerik.Windows.Controls.TreeView.TreeViewPanel.ExtendDesiredSize(ItemsControl itemsControl, Size stackDesiredSize, Int32 pivotIndex, Boolean before) in c:\TB\105\WPF_Scrum\Release_WPF\Sources\Development\Controls\Navigation\TreeView\Virtualization\TreeViewPanel.cs:line 2287
   at Telerik.Windows.Controls.TreeView.TreeViewPanel.MeasureOverride(Size constraint) in c:\TB\105\WPF_Scrum\Release_WPF\Sources\Development\Controls\Navigation\TreeView\Virtualization\TreeViewPanel.cs:line 1680

===
This item is declined because we are unable to reproduce such exception with our latest binaries.

RadTreeView is virtualized and we use ItemContainerStyleSelector. The style selector select styles which set have ExpanderStyle property. The ExpanderStyle is not applied.

There is an attached project which can be used as a possible workaround,

Available in Official Release R3 2016.

REOPEN:

The bug will be re-opened from 5 Dec 2016 internal build as well as in the official R3 2017 release.
We reverted the fix for this bug due to performance hit we found in R3 2016.
The workaround suggested in the attached project is still valid.

When you have a, for example, a RadSlider in a RadTreeViewItem and you try to move the Thumb of the slider, the drag events of the tree view item will be triggered. The same behavior is observed also when you have a TextBox instead of a slider and try to mark part of the text in it with the mouse.

Use virtualization in hierarchical mode. Select a RadTreeViewItem that has parent. Move it somewhere in the source collection of the parent programmatically - reorder or sort. The item will remain in Museover State forever.

Perform the same steps with Recycling mode, there might be missing RadtreeViewItems (not rendered at all) after the sort / reorder operation.

Select a RadTreeViewItem with MOuse and in SelectionChaged event handler disable the RadTreeView. Then when you enable it programatically, the SelectedItems's foreground is wrong.

Available in LIB Version: 2015.2.720.

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}" />

with RadTreeView control,using MVVM binding,the xaml like :
AutoScrollToSelectedItem="True"  IsVirtualizing="False"
looking the attach files,Navigate by the  RadBreadcrumb(the RadBreadcrumb and the RadTreeView binding the same data source,and binding the same SelectedIem),
when expand the level4,the RadTreeView  can't bring the selected item to view,but scroll mouse to the seleced item view,then Navigate again the same postion ,it can scroll,the radtreeview can reach the selected item.
     I test the microsoft treeview,if the Virtualizing is true,it can't scroll the selected item,but set the Virtualizing  to false,it is good.
    the other question,how to set the style?the  selected item's highligh area can expand the full row,like the visual studio.

When the IsVirtualizing property is switched on runtime (for example as a result of applied binding) the generatedContainers are not updated and potentially will not return null when a container exists.
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Marking this Declined: There is no such public collection. Too old item with only a single vote (like).