I was fiddling with the changing of a parent in the Setup screen when I got this:

That corresponds to the following trace:


Spine Launcher 1.5.1-full
Mac OS X x86_64 10.9
Java 1.7.0-u6-unofficial Oracle Corporation
OpenJDK 64-Bit Server VM
Up to date: 1.6.37
Spine 1.6.37-full, JGLFW
NVIDIA Corporation
NVIDIA GeForce GT 650M OpenGL Engine
2.1 NVIDIA-8.18.22 310.40.05f01
Started.
Uncaught
lt: index must be >= -1 and < 0: 0
	at com.badlogic.gdx.scenes.scene2d.ui.List.a(SourceFile:149)
	at ie.b(SourceFile:283)
	at id.a(SourceFile:81)
	at gw.a(SourceFile:55)
	at gq.a(SourceFile:165)
	at gq.a(SourceFile:130)
	at gy.a(SourceFile:277)
	at m.a(SourceFile:88)
	at be.a(SourceFile:81)
	at ap.e(SourceFile:209)
	at rc.e(SourceFile:160)
	at au.run(SourceFile:187)
	at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:711)
	at java.awt.EventQueue.access$000(EventQueue.java:104)
	at java.awt.EventQueue$3.run(EventQueue.java:672)
	at java.awt.EventQueue$3.run(EventQueue.java:670)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:681)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)

When I try to set the parent of an Image, I get this dialog:

http://cl.ly/image/3A0i0j0z0C3t

Now the first thing I notice is that "Existing Slot" field is empty but the image DOES currently have a slot.

If I click select the "Existing Slot" field I get the (unrecoverable) crash above.