Pool Boss editor is now broken (doesn't drop down) and you get errors: MissingReferenceException: The object of type 'Transform' has been destroyed but you are still trying to access it. Your script should either check if it is null or you should not destroy the object. UnityEngine.Component.GetComponent[T] () (at <59e7be63019b4518baaf30c245954236>:0) DarkTonic.PoolBoss.EditorScript.PoolBossInspector.OnInspectorGUI () (at Assets/DarkTonic/PoolBoss/Editor/PoolBossInspector.cs:842) UnityEditor.UIElements.InspectorElement+<>c__DisplayClass62_0.<CreateIMGUIInspectorFromEditor>b__0 () (at <6b6b0ae85ab546278d49bef5f69bb1c8>:0) UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr, Boolean&)
Only solution I can see if to delete Pool Boss and rebuild from scratch.
Switch your Inspector to debug mode and upload a screen shot for me.
Pretty easy to replicate. Add prefabs to PB, delete one of those prefabs from your assets folder then view PB in the inspector. You get something like the top image where the editor won't expand properly.