Root level exception in OnGUI(): System.InvalidOperationException: Failed to compare two elements in the array. ---> System.NullReferenceException: Object reference not set to an instance of an object at RimWorld.Planet.ExpandableWorldObjectsUtility+<>c.<SortByExpandingIconPriority>b__16_0 (RimWorld.Planet.WorldObject x) [0x00015] in <c36f9493c9844ddaa7fb5c788416098f>:0 at Verse.GenCollection+<>c__DisplayClass25_0`3[T,TSortBy,TThenBy].<SortBy>b__0 (T a, T b) [0x00000] in <c36f9493c9844ddaa7fb5c788416098f>:0 at System.Collections.Generic.ArraySortHelper`1[T].PickPivotAndPartition (T[] keys, System.Int32 lo, System.Int32 hi, System.Comparison`1[T] comparer) [0x0003d] in <567df3e0919241ba98db88bec4c6696f>:0 at System.Collections.Generic.ArraySortHelper`1[T].IntroSort (T[] keys, System.Int32 lo, System.Int32 hi, System.Int32 depthLimit, System.Comparison`1[T] comparer) [0x00069] in <567df3e0919241ba98db88bec4c6696f>:0 at System.Collections.Generic.ArraySortHelper`1[T].IntrospectiveSort (T[] keys, System.Int32 left, System.Int32 length, System.Comparison`1[T] comparer) [0x00015] in <567df3e0919241ba98db88bec4c6696f>:0 at System.Collections.Generic.ArraySortHelper`1[T].Sort (T[] keys, System.Int32 index, System.Int32 length, System.Comparison`1[T] comparer) [0x00000] in <567df3e0919241ba98db88bec4c6696f>:0 --- End of inner exception stack trace --- at System.Collections.Generic.ArraySortHelper`1[T].Sort (T[] keys, System.Int32 index, System.Int32 length, System.Comparison`1[T] comparer) [0x00020] in <567df3e0919241ba98db88bec4c6696f>:0 at System.Collections.Generic.List`1[T].Sort (System.Comparison`1[T] comparison) [0x00012] in <567df3e0919241ba98db88bec4c6696f>:0 at Verse.GenCollection.SortBy[T,TSortBy,TThenBy] (System.Collections.Generic.List`1[T] list, System.Func`2[T,TResult] selector, System.Func`2[T,TResult] thenBySelector) [0x0001e] in <c36f9493c9844ddaa7fb5c788416098f>:0 at RimWorld.Planet.ExpandableWorldObjectsUtility.SortByExpandingIconPriority (System.Collections.Generic.List`1[T] worldObjects) [0x00000] in <c36f9493c9844ddaa7fb5c788416098f>:0 at (wrapper dynamic-method) RimWorld.Planet.ExpandableWorldObjectsUtility.RimWorld.Planet.ExpandableWorldObjectsUtility.ExpandableWorldObjectsOnGUI_Patch0() at (wrapper dynamic-method) RimWorld.WorldInterface.RimWorld.WorldInterface.WorldInterfaceOnGUI_Patch1(RimWorld.WorldInterface) at (wrapper dynamic-method) RimWorld.UIRoot_Play.RimWorld.UIRoot_Play.UIRootOnGUI_Patch1(RimWorld.UIRoot_Play) at (wrapper dynamic-method) Verse.Root.Verse.Root.OnGUI_Patch1(Verse.Root) (Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 35)