Change the selection on MouseLeftButtonUp instead of MouseLeftButtonDown.

The items of the RadTreeView control do not behave correctly in a touch scenario when expanding/collapsing them.

A possible workaround for this behavior would be to set the TouchManager.ShouldSuspendMousePromotion attached property to True on the RadTreeView control instance.

The example modifies the DropPosition of the dragged item to Inside on drag over. This could lead to an exception in the default drag-drop logic if the dragged item and the drop target are of the same type. This exception causes the dragged item to disappear when it is dropped.

RadTreeView with virtualization turned on, defines HierarchicalDataTemplates for its items. 

In the template, the root panel is 32 pixels (or higher than the default TreeViewItemHeight - 24 px in OfficeBlackTheme). Scrolling the treeview, then maximizing the wpf window results in misplaced / incorrect height of treeviewitems.

Possible workaround:
Set the MinHeight property of RadTreeViewItem so that all its header content fits. Then set the item's VerticalContentAlignment to Stretch
        <Style TargetType="telerik:RadTreeViewItem">
                         <Setter Property="MinHeight" Value="48" />
                        <Setter Property="VerticalContentAlignment" Value="Stretch" />
                   </Style>

Also following settings might help:
   - setting fixed width/height of the RadTreeView
   - setting ChildDefaultLength to 48 of every TreeviewPanel:
			<telerik:RadTreeView.ItemsPanel>
				<ItemsPanelTemplate>
					<telerik:TreeViewPanel ChildDefaultLength="48" />
				</ItemsPanelTemplate>
			</telerik:RadTreeView.ItemsPanel>
        <Style x:Key="ItemContainerStyle" TargetType="{x:Type telerik:RadTreeViewItem}">
			<Setter Property="ItemsPanel">
				<Setter.Value>
					<ItemsPanelTemplate>
						<telerik:TreeViewPanel ChildDefaultLength="48" />
					</ItemsPanelTemplate>
				</Setter.Value>
			</Setter>

Setting custom ItemContainerStyleSelector is sometimes not applied to every item of the RadTreeView control, when the TreeVirtualizationMode is set to Hierarchical.

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).

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)

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

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. 

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

This behavior is observed in the Office2016 theme.

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

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;
}

Hi,

I found a bug when drag&dropping selected tree nodes (extended multi-selection) when the tree is virtualized. Items that never got into view are missing from the Payload Manager Data object. If virtualization is off, works as expected.

Please see modified sample for demonstration. I added 200+ items to League A -> Division A. Select the first item, quickly scroll by dragging vertical scrollbar to the bottom of the list and extend selection to the whole list. Then perform drag and drop. Note, not all items were moved.

Also, the drag visual helper moves and updates very very slowly when dragging hundredths of objects. In our application, we have thousands of objects, which makes it unusable

 

Thank you for a quick fix.

Tomas.

SelectedItems collection not updated when items are removed

Virtualized TreeView is bound to collection of models and IsSelected of RadTreeViewItem is 2way bound to IsSelected of model.

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).

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

Currently when the UI Virtualization is enabled, the RadTreeView sets the IsExpanded property of the RadTreeViewItems to False when they don't have any children. We can add a mechanism by which this can be stopped. 

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.