Bug: Crashes after opening the properties window twice

[hishitetsu]

Description

No error is logged, but a NullPointerException is thrown at

Files/src/Files.App/Helpers/UI/DragZoneHelper.cs

Line 28 in bc00d61

var scaleFactor = uiElement.XamlRoot.RasterizationScale;

Steps To Reproduce

1. Open a properties window.
2. Close it.
3. Open the window again.
4. Observe a crash.

Requirements

Fix crash.

Files Version

3.1.0.0

Windows Version

10.0.22631.2861

Log File

debug.log

[yaira2]

This might be a result of the changes in #14342