Subject
When using a RadListBox with a VirtualizingWrapPanel as ItemsPanel and the ScrollUnit is set to Pixel, the previously selected item stays like an overlay that can be interacted with if the ItemWidth and ItemHeight are changed.
Attached Files
The attached files contain a demo application, which is a minimal sample to reproduce the problem. Due to the file upload size limitation, the referenced Telerik DLLs for the sample project are not contained.
Description
Exemplary Scenario
A RadListBox with a VirtualizingWrapPanel as ItemsPanel is used to display a collection of strings. The ScrollUnit is set to Pixel. The size of the items can be adjusted with a button that toggles these sizes: Small, Medium and Large. The current size is displayed in a TextBlock. The sizes are defined as an enum and mapped to ItemWidth and ItemHeight in a Style.
Steps to Reproduce
- Start the application.
- Scroll an item into the center of the viewport, leaving space around it.
- Select the item.
- Click the "Toggle Layout" button.
Result
The previously selected item in its original size still exists, is selected, immovable and clickable.
Expectation
All items are displayed using the new size and the corresponding item is selected. There are no duplicate items or leftover items with the previous size.
Issue Characteristics
- Only occurs when ScrollUnit is set to Pixel.
- Occurs in multiple themes like Office2016, Office2019, Windows11, but not in Fluent.
- The repro steps can be repeated multiple times which will lead to multiple different overlays.
- An item must be in the center of the viewport. With items on the edge of the RadListBox like Item 1 or others that are selected from below and are scrolled into view to the bottom edge of the viewport, the issue is not reproducible.
- Is reproducible at least since Telerik UI for WPF 2022.1.222, including the current Version 2022.2.621.
