BPC 10.1 - Time Dependent Hierarchy

Hi,

I created a User Defined Dimension in 10.1 wanting to test the Time Dependent Hierarchy but I am running into inability to

turn that fucntionality on. When I create the dimension and check the "Time Dependent Hierarchy" checkbox on the Structure of Dimension screen it prompts me to save the new setting. As soon as I save the checkbox becomes unchecked. Any advice, hints?

thank you

Paul