Stair "Relative Top Height Parameter"??

[vanderloo5]

Trying to change a stair config to smaller risers, and when I enter the max riser height and apply. I get a message saying I need to change the stair's relative top height parameter in the properties palette.
No such parameter in my properties palette.
What might I be missing?
Thanks

[Duncan Lithgow]

Have you opened edit Stair and then selected the run? Depending on how the stair is build you should be able to edit the value or the 'Relative Bottom Height' value. I'm assuming you're using the Stair by Component tool.