I see exactly what you want to do, with the current version of the Widget Pack, it can not be done … with the forthcoming category widget in Widget Pack 2.0 however you can very easily crerate multiple category widget for the sidebar
oh, wait…. reading this again, I think I misunderstood…
Is this question related to the Widget Pack?
The category widget in the Widget Pack simply output a list of links of categories. If you’re familiar with the category widget for WordPress; same thing.
I have a feeling that you’re asking for multiple category search. For example, cMap has a searchable category drop down … are you actually asking about have multiple searchable category drop downs?