crashing when adding behaviors in pony editor

[briskbronco2006]

Hello! I keep getting this error whenever I try to add behaviors for custom ponies. It seems to only show up for idle animations and drag/hover animations. I tried manually editing the config and that seemed to work at first, but it crashed seconds later. Is there a way to fix this issue? Is there a file I'm missing? Any potential mistakes I might've made? Thank you!

Error in full:

System.IndexOutOfRangeException: Index was outside the bounds of the array.
at System.Windows.Forms.Control.EndInvoke(IAsyncResult asyncResult)
at DesktopSprites.Core.ControlExtensions.CrossThreadInvoke(Control control, Action action) in _______________________________________________Desktop Ponies\Desktop Sprites\Core\ControlExtensions.cs:line 87
at DesktopSprites.Core.ControlExtensions.TryInvoke(Control control, Action action) in _______________________________________________Desktop Ponies\Desktop Sprites\Core\ControlExtensions.cs:line 39
at DesktopSprites.SpriteManagement.WinFormSpriteInterface.Draw(ICollection`1 sprites) in _______________________________________________Desktop Ponies\Desktop Sprites\SpriteManagement\WinFormSpriteInterface.cs:line 1616
at DesktopSprites.SpriteManagement.AnimationLoopBase.Draw() in _______________________________________________Desktop Ponies\Desktop Sprites\SpriteManagement\AnimationLoopBase.cs:line 1268
at DesktopSprites.SpriteManagement.AnimationLoopBase.Run(Object startSync) in _______________________________________________Desktop Ponies\Desktop Sprites\SpriteManagement\AnimationLoopBase.cs:line 1162
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart(Object obj)