TreeView: Dragging and dropping a selected item in single selection mode causes the item to be unselected

[Felix-Dev]

Describe the bug
Given a TreeView in single-selection mode, dragging and then dropping a selected item causes the item to be unselected:

I view this as a bug. A drop should not cause the selected item to be unselected. In fact, it works as expected in multi-selection mode:

(The issue you see in the above where the parent nodes' selection state is not updated after the drag and drop operation is being tracked in issue #3092.)

Steps to reproduce the bug

Steps to reproduce the behavior:

1. Open the XAML Controls Gallery and go to the TreeView page
2. Scroll down to the single-selection TreeView drag and drop example
3. Do the same (or similar) steps as shown in the GIF.

Expected behavior
The drag & drop'ed TreeViewItem should remain selected:

Version Info

NuGet package version:
WinUI 2.4 and WinUI 2.5 previews

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
May 2020 Update (19041)	Yes
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context
I would like to fix this.

[StephenLPeters]

Single selection we are inheriting from list view and multi select we rolled our own solution, so i'm not surprised there is differences. Interestingly list view does keep selection during drag and drop, so we must be doing something to affect it.

[github-actions]

This issue is stale because it has been open 180 days with no activity. Remove stale label or comment or this will be closed in 5 days.