SelectionChanging event could be added for preventing selection in code, just like SelectionChanging event in RadGridView and PreviewSelectionChanged in RadTreeView

ArgumentOutOfRangeException is thrown when calling the ScrollIntoView method with an invalid index and the control is grouped.

Scheduled for:
The fix for this issue will be available with LIB (version 2018.3.1210) scheduled for publishing on Monday, 10th December 2018.

If you host a RadMaskedTextInput control in the listbox items and focus the input, then pressing Space will send the focus to the corresponding RadListBoxItem instead of adding an empty space character into the text input.

To work this around, create a custom RadListBox control and override its HandleKeyboardInput method.

If you set the SelectedIndex after an item is added in the Items or ItemsSource of RadListBox, the selection doesn't work. 

To work this around, use the SelectedItem property instead of SelectedIndex.

The selected item is scrolled out of view if the ItemsSource is changed during runtime and IsScrollIntoViewEnabled is True.

In this particular case, the RadListBox is placed inside RadBusyIndicator. When we set the DragDropManager.UseAdornerLayer static property to true, drop functionality is restricted. A possible workaround here is to avoid using RadListBox as a content of RadBusyIndicator

 Extremely bad selection performance with large numbers of items (above 10K).

Improve the performance when selecting a large number of items, using Ctrl + A, for example.

The LinearDropVisual element is not displayed below the last item in a drag-drop scenario when ScrollViewer.CanContentScroll is set to False.

Currently, when a RadListBoxItem container is selected it will be highlighted and scrolled to, which causes the ScrollViewer to "auto-scroll". We could add option to enable/disable this scrolling behavior.

When the ItemsSource of the control is changed to a new collection the old selected items are cached and if a collection containing the old selected items source is set as ItemsSource the cached items are restored.

Make it possible to disabled this functionality per control.

Available in the 2017 R1 Release (2017.1.117).

The "auto scroll into the view on selection" functionality does not to work as expected if the ItemsPanel is changed and a selection was previously done.

Available in the 2016 Q1 Release.

Can be reproduced when RadListBox is placed inside a Grid, a StackPanel with horizontal orientation or a WrapPanel.

Available in LIB version 2016.1.125, it will be also available in the 2016 Q1 SP1.

The issue can be reproduced in a scenario in which there are a RadListBox and a RadGridView defined and their SelectedItem properties are bound to the same property in the view model. The source collection of RadListBox contains some objects present in the one bound to RadGridView's ItemsSource. If the user selects an item in RadGridView that is also present in the items of RadListBox, the selection is performed in both controls as expected. However, when already having a selected item in both controls, if the user selects an item in RadGridView that is not present in the items of RadListBox, the selection in RadListBox is not cleared. Thus, in order to selected the previously selected item, it needs to be deselected and selected again.

UPDATE:
After the researching the issue, it seems that the logic for handling the case when a SelectedItem that is not present in the source collection is being set is slightly different for Silverlight and WPF. For the WPF version of the control a DependencyProperty.UnsetValue is used, whereas a null value is set for the Silverlight RadListBox. Thus, in Silverlight the selection is cleared and in WPF it is not. I am afraid, that we cannot commit ourselves to modifying this by-design implementation, as this will result in a braking change. With this in mind, I will update the status of the logged bug to Declined.

What we can suggest as a workaround, would be to define a second calculated property in the view model and bind the SelectedItem of RadListBox to it. The logic in the property setter would be to set a null value if the SelectedItem is not present in the source collection of RadListBox.

This behavior is also reproduced in RadFileDialogs in the FileBrowserListBox which inherits RadListBox.

As a workaround you can set the IsScrollIntoViewEnabled property of the RadListBox to false

The border of the RadListBox is missing in the Office2019 theme if System.Windows.xaml resource dictionary is not merged.