PropertyDrawer not working

[szyuGH]

I'm using Unity 2021.3.19f1 with the SerializableDictionary package.

I created a class for my Dictionary and added another class in an Editor folder:

[Serializable]
public class StatMap : SerializableDictionary<string, int> {}

and

[CustomPropertyDrawer(typeof(StatMap), true)]
public class AnySerializableDictPropertyDrawer : SerializableDictionaryPropertyDrawer {

    public override void OnGUI(Rect position, SerializedProperty property, GUIContent label) {
        base.OnGUI(position, property, label);
     } 
}

I override the OnGui method so I can place a breakpoint. But no matter what I do, the breakpoint is never reached. I have an auto property inside my PlayerCharacter script and the inspector looks like this:

Has anyone a solution on how to get the property drawer working?