the unity options window , type, when i click the plus button it wont open the search window, i get this error
NullReferenceException: Object reference not set to an instance of an object
Opsive.Shared.Editor.UIElements.FilterWindow.Initialize (UnityEditor.EditorWindow sourceWindow, System.Type[] baseTypes, Opsive.Shared.Editor.UIElements.FilterWindow+FilterType filterType, System.String title, System.Boolean showCollectionType, System.Object selectedObject, System.Action`3[T1,T2,T3] onSelection) (at <d64ce463719e4c3ea88be690b831f279>:0)
Opsive.Shared.Editor.UIElements.FilterWindow.ShowFilterWindow (UnityEditor.EditorWindow sourceWindow, UnityEditor.Experimental.GraphView.SearchWindowContext context, System.Type[] baseTypes, Opsive.Shared.Editor.UIElements.FilterWindow+FilterType filterType, System.String title, System.Boolean showCollectionType, System.Object selectedObject, System.Action`3[T1,T2,T3] onSelection) (at <d64ce463719e4c3ea88be690b831f279>:0)
Opsive.Shared.Editor.UIElements.UnitOptionsWindow+<DisplayAvailableTypes>c__AnonStorey1.<>m__2 () (at <d64ce463719e4c3ea88be690b831f279>:0)
Opsive.Shared.Editor.UIElements.ReorderableList.<ReorderableList>m__1 () (at <d64ce463719e4c3ea88be690b831f279>:0)
UnityEngine.UIElements.Clickable.Invoke (UnityEngine.UIElements.EventBase evt) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.Clickable.ProcessUpEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.Vector2 localPosition, System.Int32 pointerId) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.Clickable.OnMouseUp (UnityEngine.UIElements.MouseUpEvent evt) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventCallbackFunctor`1[TEventType].Invoke (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.PropagationPhase propagationPhase) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventCallbackRegistry.InvokeCallbacks (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.PropagationPhase propagationPhase) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.CallbackEventHandler.HandleEvent (UnityEngine.UIElements.EventBase evt) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.TextElement.HandleEvent (UnityEngine.UIElements.EventBase evt) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.CallbackEventHandler.HandleEventAtTargetPhase (UnityEngine.UIElements.EventBase evt) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.MouseCaptureDispatchingStrategy.DispatchEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcher.ApplyDispatchingStrategies (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, System.Boolean imguiEventIsInitiallyUsed) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEventQueue () (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcher.OpenGate () (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcherGate.Dispose () (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcher.ProcessEvent (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.EventDispatcher.Dispatch (UnityEngine.UIElements.EventBase evt, UnityEngine.UIElements.IPanel panel, UnityEngine.UIElements.DispatchMode dispatchMode) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.BaseVisualElementPanel.SendEvent (UnityEngine.UIElements.EventBase e, UnityEngine.UIElements.DispatchMode dispatchMode) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.UIElementsUtility.DoDispatch (UnityEngine.UIElements.BaseVisualElementPanel panel) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.UIElementsUtility.UnityEngine.UIElements.IUIElementsUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& eventHandled) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.UIEventRegistration.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.UIElements.UIEventRegistration+<>c.<.cctor>b__1_2 (System.Int32 i, System.IntPtr ptr) (at <02231d46709e4238b32c60d30a79e0b6>:0)
UnityEngine.GUIUtility.ProcessEvent (System.Int32 instanceID, System.IntPtr nativeEventPtr, System.Boolean& result) (at <69ded5aee0a54ef3a96d5bab3ff941d1>:0)