The RadPropertyGrid implementation should be improved in a way that will allow users to override the methods that fire events like: OnEditorRequired, OnEditorInitialized, OnCustomGrouping etc.
Resolution:
1. Inherit from PropertyGridTableElement and override the method you want.
2. Inherit from PropertyGridSplitElement and override the CreateTableElement() return your class from 1.
3. Inherit from PropertyGridElement and override the CreateSplitElement() return your class from 2.
4. Inherit from RadPropertyGrid and override the CreatePropertyGridElement() return your class from 3.