Clear data from dashboards?

We're in our 1st month of Vantage 8.00.10b, so very new to this. I've
developed dashboards and notice some quirks. What I expect the
datafields in the tracker search window to do is return a zero value
if no data is found. Yet I find that the value of the prior search is
retained in those fields not enabled as dashboard prompts if no value
is available. Is there a method to make this happen? For instance, the
search on a PN brings in qty in stock, sales & mfg demand, and vendor
qty on order. Vendor qty on order remains at last search value if on
the next search there is none of that PN on order from a vendor.
thx