Combobox Filter Rows Issue

HI All

When using the combobox Filtered Rows functionality to pick a subset of rows from a source of data and to place the subset of data into a destination cell range, upon making the second data selection, i.e., first selection uses 01.2010 and grabs 5 rows, the second time, when selecting 02.2010, that has 10 rows of associated data, the destination range appears to still have data from the selection in the target range left in it. Is there some prerequisite to cleaning out the target range between selections?