rimworld error

Exception filling window for RimWorld.Page_ConfigureIdeo: System.ArgumentNullException: Value cannot be null.
Parameter name: key
  at System.Collections.Generic.Dictionary`2[TKey,TValue].FindEntry (TKey key) [0x00008] in <eae584ce26bc40229c1b1aa476bfa589>:0
  at System.Collections.Generic.Dictionary`2[TKey,TValue].ContainsKey (TKey key) [0x00000] in <eae584ce26bc40229c1b1aa476bfa589>:0
  at RimWorld.IdeoStyleTracker.StyleForThingDef (Verse.ThingDef thing, RimWorld.Precept precept) [0x00000] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.Ideo.GetStyleAndCategoryFor (Verse.ThingDef thingDef) [0x0003a] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.Ideo.GetStyleFor (Verse.ThingDef thingDef) [0x00000] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.Precept_Weapon.DrawIcon (UnityEngine.Rect rect) [0x0009c] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.Precept.DrawPreceptBox (UnityEngine.Rect preceptBox, RimWorld.IdeoEditMode editMode, System.Boolean forceHighlight) [0x00498] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.IdeoUIUtility.DoPreceptsInt (System.String categoryLabel, System.String addPreceptLabel, System.Boolean mainPrecepts, RimWorld.Ideo ideo, RimWorld.IdeoEditMode editMode, System.Single& curY, System.Single width, System.Func`2[T,TResult] filter, System.Boolean sortFloatMenuOptionsByLabel) [0x00f2b] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.IdeoUIUtility.DoPrecepts (System.Single& curY, System.Single width, RimWorld.Ideo ideo, RimWorld.IdeoEditMode editMode) [0x00186] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.IdeoUIUtility.DoIdeoDetails (UnityEngine.Rect inRect, RimWorld.Ideo ideo, UnityEngine.Vector2& scrollPosition, System.Single& viewHeight, System.Boolean editMode, System.Action`1[T] ideoLoadedFromFile, System.Boolean showSaveLoadBtns) [0x00124] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.IdeoUIUtility.DoIdeoListAndDetails (UnityEngine.Rect fillRect, UnityEngine.Vector2& scrollPosition_list, System.Single& scrollViewHeight_list, UnityEngine.Vector2& scrollPosition_details, System.Single& scrollViewHeight_details, System.Boolean editMode, System.Boolean showCreateIdeoButton, System.Collections.Generic.List`1[T] pawns, RimWorld.Ideo onlyEditIdeo, System.Action createCustomBtnActOverride, System.Boolean forArchonexusRestart, System.Func`2[T,TResult] pawnIdeoGetter, System.Action`1[T] ideoLoadedFromFile, System.Boolean showLoadExistingIdeoBtn, System.Boolean showSaveLoadBtns) [0x00165] in <f81f052e138344458cc870569c2ab66f>:0
  at RimWorld.Page_ConfigureIdeo.DoWindowContents (UnityEngine.Rect rect) [0x00033] in <f81f052e138344458cc870569c2ab66f>:0
  at Verse.Window.InnerWindowOnGUI (System.Int32 x) [0x001ce] in <f81f052e138344458cc870569c2ab66f>:0
(Filename: C:\buildslave\unity\build\Runtime/Export/Debug/Debug.bindings.h Line: 39)

GUI Error: You are pushing more GUIClips than you are popping. Make sure they are balanced.
(Filename:  Line: 580)