Steps to reproduce:
1. Create a form that is MDI Parent
2. Create a form that would be and MDI Child.
3. Add a RadSplitButton to the MDI Child form and set it's anchor to Bottom | Left.
4. Set the WindowState of the MDI Child to be Maximized.
5. In a Form.Load event handler of the MDI Parent add an MDI Child form.
Run the project and you will see that the RadSplitButton is in the wrong location.