Drill up issue

[Anonymous]

I have a drill-down group consisting of 5 dimension, one of them being 'Sales Territory'.  An issue occur when I do this:

- Select a value for Sales Territory parameter

- Drill down on this group (to members of a particular territory)

- When I drill back up, the Sales Territory selection disappears, and show all territories

Why would drilling up deselect my Sales Territory? Is that a feature or bug?