Approved
Last Updated: 17 Jul 2019 11:31 by ADMIN

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. 

Approved
Last Updated: 30 Jul 2018 08:13 by ADMIN
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);
Approved
Last Updated: 05 Apr 2018 10:34 by ADMIN
The built-in drag drop mechanism works with the containers of the items and makes a snapshot of them for the DragVisual. Thus, dragging multiple selected items that are not present in the viewport is not possible.
Approved
Last Updated: 04 Dec 2017 15:47 by Vladimir
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.
Approved
Last Updated: 03 May 2017 11:18 by ADMIN
ADMIN
Created by: Martin Ivanov
Comments: 0
Category: TreeView
Type: Bug Report
0
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>
Approved
Last Updated: 29 Dec 2016 14:43 by ADMIN
The vertical scroll cannot be moved via the mouse wheel or by clicking on the scrollbar's thumb after the End key is pressed. This is reproducible ONLY if the UI virtualization is enabled and if there are many items (500-1000+).
Approved
Last Updated: 19 Mar 2019 15:39 by ADMIN
Currently, in Extended SelectionMode,  RadTreeView selects multiple Items with Shift + Click selection only if there is another RadTreeViewItem already selected with mouse.

Other controls like RadListBox, RadGridView hold reference to the business object which should be the start (the target) of the multiselection. RadTreeView holds such reference with weak reference to the container (RadTreeViewItem) and only if this container is selected with Mouse.

Adding such method (SetSelectionAnchor) in RadTreeView will help users better control the multiselection process.
Approved
Last Updated: 03 Jan 2017 20:55 by ADMIN
ADMIN
Created by: Martin Ivanov
Comments: 0
Category: TreeView
Type: Feature Request
1
Expose properties that controls the lines color and their thickness like in the RadTreeListView.
Approved
Last Updated: 28 Dec 2016 15:13 by rousso
TreeView Virtualization Mode is Recycling (the default one). In the ItemTemplate there is a RichTextBox with HtmlFormatProvider. Changing ItemsSource of the TreeView runtime produces null reference exception in TreeViewPanel.CleanupRange().
The Exception comes from the RecyclingItemContainerGenerator.Recycle method (http://msdn.microsoft.com/en-us/library/cc452208(v=vs.110).aspx). 
As a workaround if applicable, user can use the HierarchicalVirtualization mode:
    <telerik:RadTreeView  telerik:TreeViewPanel.TreeVirtualizationMode="Hierarchical"
Approved
Last Updated: 29 Dec 2016 14:26 by ADMIN
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.
Approved
Last Updated: 27 Dec 2016 11:27 by Yanming
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.
Approved
Last Updated: 03 Jan 2017 21:19 by ADMIN
ADMIN
Created by: Petar Mladenov
Comments: 0
Category: TreeView
Type: Feature Request
1
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.
Approved
Last Updated: 03 Jan 2017 21:09 by ADMIN
RadTreeView is virtualized and SelectionMode is set to "Extended". All ViewModels are selected and IsSelected of TreeViewitems is 2-way bound to IsSelected in the ViewModels. When clicking a TreeViewitem with Mouse, all other items are deselected. However, when scrolling we see that items are being prepared are not deselected - they are still selected.

This is due to a Limitation of the Virtualization mechanism - it does not know about the existance of the ViewModels and does not work with them. Virtualization works only with the Containers - the RadTreeViewItem.
Approved
Last Updated: 29 Dec 2016 16:01 by ADMIN
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.

Another workaround: Use visibility instead of Width=0.
Approved
Last Updated: 05 Jan 2017 08:00 by ADMIN
This will solve scenarios in which user wants to add new items somewhere (inner level, outside the ViewPort ) in virtualized treeview and then wants to begin edit these items (or focus them , select them). 
There is currently no mechanism to detect when the new items are ready (measured / completely generated), ItemsPrepared for example passes before the OnApplyTemplate of the RadTreeViewItem.
Approved
Last Updated: 27 Dec 2016 12:46 by ADMIN
RadTreeView and RadTreeViewItem ExpandAll() method sets the IsExpanded property to True to all items even if an Item has no children to display. This causes an issue when using the DefaultImageSrc and ExpandedImageSrc properties as the last-level items will be displayed with an ExpandedImageSrc as their IsExpanded property it set to True. However, as these items have no children, they should use the DefaultImageSrc.
Approved
Last Updated: 25 Nov 2016 16:38 by ADMIN
Root level items ItemTemplate is incorrectly set after virtualization when using HierarchicalDataTemplate with ItemTemplateSelector.
This causes the second level items to use incorrect data template.
Approved
Last Updated: 29 Dec 2016 16:03 by ADMIN
Rendering issues occure when using Hierarchical virtualization mode and bring into view.
The issue is hit in both platforms - WPF and Silverlight. 
Approved
Last Updated: 29 Dec 2016 15:16 by ADMIN
Scenario: Databound TreeView with IsSelected bindings between item and container. Adding a selected data object to the ItemsSource does not fire the Selected event.
Approved
Last Updated: 27 Dec 2016 12:22 by ADMIN
We have RadContextMenu in RadTreeView when we press the App key or shift+F10 the context menu opens as intended but it triggers the parent TreeViewItem hover effect
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