When I use a multi-level dimension from an OLAP cube (running on SQLServer
200 AS box) and put it in the row area I can drill down on it until I get to
the lowest level, in this case the 4th level (Year/Qtr/Month/Week) no
problems.

If I then filter this dimension to select each and every week in Jan/Feb/Mar
for any specific year the results I get only allow me to drilldown to the
second level of the dimension. The +/- button in front of the year level
allows me to expand/collapse to the next level. But the +/- button in front
of the next level (quarter) just disappears or returns when I double click on
the field.

If I remove the filter and select all of the dates, then my ability to
drilldown to the lowest level returns.

I just don't understand why when I am filtering for say a specific year why
I am no longer able to drilldown below the quarter level of the dimension.

Any help would be appreciated.