Custom Inspector Undo

I have the following in a very simple custom editor. If I change the value and hit ctrl+z, it does not undo the value change, but instead reverts to the last operation on the undo stack (Selection Change). What do I need to do to this code to make it properly work with ctrl+z?

If I leave it using the default inspector, ctrl+z works as it should.

Code (CSharp):

1.             public override void OnInspectorGUI()
2.             {
3.                 _target.Field = EditorGUILayout.FloatField("Field Value:", _target.Field);
4.     }

 

Code (CSharp):

1. EditorGUI.BeginChangeCheck()
2.  
3. float newValue = EditorGUILayout.FloatField("Field Value:", _target.Field);
4.  
5. if (EditorGUI.EndChangeCheck()) {
6.  
7.     Undo.RecordObject(_target, "Set Field Value");
8.  
9.     _target.Field = newValue;
10. }

 

Thanks, this worked, but Undo.RecordObject does not work for me. I have to use Undo.RegisterUndo for some reason.