Random crash setting themes up

[Former user]

System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource) at System.Collections.Generic.List`1.get_Item(Int32 index) at (TextFiltersViewModel ) at Unbroken.LaunchBox.Wpf.BigBox.ViewModels.TextFiltersViewModel.OnPageDown() at (MainViewModel ) at Unbroken.LaunchBox.Wpf.BigBox.ViewModels.MainViewModel.OnPageDown() at Unbroken.LaunchBox.Wpf.BigBox.ViewModels.MainViewModel.<>c__DisplayClass210_0.<HandleJoystickButton>b__0() at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs) at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

[Jason Carr]

Thank you Anonymous; this has been fixed for the next beta.