[Bug]: ClassCastException when using Arrange -> Send to Back from Draw Explorer

[Phergus]

Describe the Bug

Attempting to change the Z order of drawings using Send to Back from the Draw Explorer can produce a ClassCastException.

To Reproduce

1. Load attached campaign.
2. Open Draw Explorer if not open.
3. Under Background select the green rectangle (width(185) height(121)).
4. Right-click to access Arrange -> Send to Back.
5. Get error dialog with CCE.
6. Drawing is removed from map.

Error:

java.lang.ClassCastException: class java.util.ArrayList cannot be cast to class java.util.LinkedList (java.util.ArrayList and java.util.LinkedList are in module java.base of loader 'bootstrap')
	at net.rptools.maptool.model.Zone.addDrawableRear(Zone.java:1329)
	at net.rptools.maptool.client.ui.drawpanel.DrawPanelPopupMenu$SendToBackAction.actionPerformed(DrawPanelPopupMenu.java:321)
	at java.desktop/javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
...

Expected Behaviour

Expect drawing to be pushed to back.

Screenshots

Before attempting change.

MapTool Info

MT 1.12.0 alpha 1

Desktop

Windows 10

Additional Context

Campaign file. Remove .zip extension.
Drawing Order.cmpgn.zip

[Phergus]

Tested changes. Working as expected now.