Combo box bound parameter returns no entry when workflow time changed

Hi,

We have combo boxes in a dashboard that use an XFBR to define a UD1 (Cost Centre) list based on the text 2 field from the users current workflow. For example, if a user is in the North America workflow the combo box will only display North America & below. When a user changes their workflow & returns to the dashboard if their last selection isn't present in the new hierarchy the combo box will display a blank result. Is there a way to prevent this?

We also have a similar issue where a combo box contains 2 parameters, 1 that defines the prior month & another for prior year. If the workflow time is changed these also return blank when the dashboard is opened.

Thanks,