ShowLocalAxisInspector.cs

using UnityEngine;
using UnityEditor;

// This custom Inspector just shows the default inspector and
// then, at the correct time, destroys the component if it has
// been flagged for destruction.
[CustomEditor(typeof(ShowLocalAxis))]
public class ShowLocalAxisInspector : Editor
{
    public override void OnInspectorGUI()
    {
        // Draw the standard inspector.
        base.DrawDefaultInspector();  

        // Get the reference to the ShowLocalAxis component in the inspector.
        ShowLocalAxis showRotated = (ShowLocalAxis)target; 
        
        // If the CustomTransforInspector class has set the ShowRotated component to be destroyed
        // then if the inspector's event state is Repaint it is save to actually destroy the component.
        if (showRotated.destroyWhenSafe && Event.current.type == EventType.Repaint)
        {
            DestroyImmediate(showRotated);
            return;
        }
    }
}