We use a RadTreeView with many different item types that set a DefaultImageSrc based on a combination of item type and state
(from each item's view model).

For the currently selected TreeView item we would like to modify the item's image with a coloured border.
So it would be a very useful feature, if the TreeView item's SelectedImage could be derived from the DefaultImageSrc
via XAML Shapes (Rectangle, Line, etc.).
(Shapes can e.g. already be used to draw TreeView's Expander-Button for expanded/collapsed state, which is very useful).

Currently the only approach is to copy any item-type's image in the file system and modify it for selected state.
(Thus doubling the number of item image files.)
Given the number of images for different item types and states that we already have, this is not very practical.

Examples for DefaultImageSrc (left) and SelectedImageSrc (right):

•  -> 
•  -> 

Is it possible to extend RadTreeView, so that the SelectedImageSrc can be based on the given DefaultImageSrc, but with a modification provided via XAML?

Setting the color variation of the VisualStudio2019Palette to ColorVariation.Dark of the VisualStudio2019 theme makes the TreeViewItem elements difficult to read (gray foreground on a white background).

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

When a large number of items are selected through extended selection (with a lot of items on the first level of the RadTreeView) the selection does not work correctly. 

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 sorting a table I get the following stacktrace.

06.12.2016 15:39:34 Error General Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Windows.Controls.ItemContainerGenerator.Remove(GeneratorPosition position, Int32 count, Boolean isRecycling)
   at Telerik.Windows.Controls.TreeView.TreeViewPanel.CleanupRange(IList children, IItemContainerGenerator generator, Int32 startIndex, Int32 count)
   at Telerik.Windows.Controls.TreeView.TreeViewPanel.CleanupContainers(Int32 firstViewport, ItemsControl itemsControl)
   at Telerik.Windows.Controls.TreeView.TreeViewPanel.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
   at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
   at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged)
   at System.Windows.Controls.Grid.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at System.Windows.Controls.Control.MeasureOverride(Size constraint)
   at Telerik.Windows.Controls.RadTreeViewItem.MeasureOverride(Size availableSize)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at Telerik.Windows.Controls.TreeView.TreeViewPanel.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at MS.Internal.Helper.MeasureElementWithSingleChild(UIElement element, Size constraint)
   at System.Windows.Controls.ItemsPresenter.MeasureOverride(Size constraint)
   at System.Windows.FrameworkElement.MeasureCore(Size availableSize)
   at System.Windows.UIElement.Measure(Size availableSize)
   at System.Windows.Controls.Grid.MeasureCell(Int32 cell, Boolean forceInfinityV)
   at System.Windows.Controls.Grid.MeasureCellsGroup(Int32 cellsHead, Size referenceSize, Boolean ignoreDesiredSizeU, Boolean forceInfinityV, Boolean& hasDesiredSizeUChanged)
...

When this property is set to false the changes are not saved.

Edit:
We have reviewed this item and we can confirm this is by design and it is not bug. IsInEditMode serves only for opening / closing the edit mode of the RadTreeViewItem. 
The way to submit changes is to use CommitEdit() method.

A common request is to have a way to hide the root node of a RadTreeView so that the second-level nodes are displayed without a root.  If the RadTreeView is bound, it appears that this can be done through the hierarchical binding if one know what one is doing.  However, there does not seem to be a simple way to do it if the nodes to be added to the RadTreeView are added programmatically.  It would be helpful if there were a binary property on the RadTeeView to set whether the root node is displayed.


Reason for decline:
Both in databound tree or not , you can add only the items you need to display in the root source / root items collection of the tree. Generally, there is no value of hiding a root node that has children - why is inside the collection at all ?

Change the selection on MouseLeftButtonUp instead of MouseLeftButtonDown.

DECLINED: Duplicate with https://feedback.telerik.com/Project/143/Feedback/Details/112812-treeview-perform-selection-on-mouseleftbuttonup

The DefaultImageSrc property doesn't show the image when it is set to a relative file path.
Reason for Decline: This is not actually a bug. When you set the DefaultImgSrc in XAML starting with "/" the Image is shown successfully. In WPF the relative image sources must begin with "/".

http://msdn.microsoft.com/en-us/library/aa970069%28v=vs.110%29.aspx 

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.

When the TreeView's ScrollViewer is Visible, changing the tree's width to 0 them back to Auto breaks the scrolling function of the ScrollViewer.
The workaround is to make the TreeView Collapsed before setting the Width to 0 and make it Visible before setting the Width back to Auto.

Reason for declination: 
The feedback item is declined due to duplication with the one below:
http://feedback.telerik.com/Project/143/Feedback/Details/113789-treeviews-scrolling-does-not-work-if-the-trees-width-is-set-to-0-and-then-back
Please follow it instead. 

When the ScrollViewer of a virtualized TreeView is visualized the bindings of the TreeViewItem are broken.

We are closing this one because of duplication with the following item => http://feedback.telerik.com/Project/143/Feedback/Details/112754-treeview-bindingexpressionerror-occurs-in-situations-when-the-tree-is-virtualiz 

The CheckedItems  collection is not cleared when ItemsSource is changed.

Please consider CheckedItems as not supported collection in RadTreeView. In DataBinding scenarios , use the approach described in the following article:
http://docs.telerik.com/devtools/wpf/controls/radtreeview/how-to/howto-tri-state-mvvm.html 
This way you will be able to create CheckedItems property in your ViewModels.

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 using binding to check state and dynamically adding subitem to a praticular items, the parent items check state is incorrectly set to Off (from ON) although the child item state is also On.

Marking this Declined. Binding to CheckState is not supported in MVVM scenarios. Please use the approach described here =>
http://www.telerik.com/help/wpf/radtreeview-howto-tri-state-mvvm.html

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

The issue is not reproducible with R3 2016 Release.

When value types are inserted in the Items collection of RadTreeView and root values are duplicated in the children a StackOverflowException is raised after a call to ExpandAll.

The XAML has recently reviewed the status of this issue and won't be addressing it in future releases.
This is a design limitation - RadTreeView does not support duplication of value types in its Items / ItemsSource collections. 
This potentially can cause troubles with virtualization / selection / expandALL features.

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

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.