If your QB Maps buttons still generate like the following image, you're on an older version of QB Maps and should upgrade to get the latest features and UI.
Step 1: Create a new field in the table with the button that generates QB Maps, and call it exactly Legend Properties.
Learn how to fill in this field in the Legend Properties setup guide
Step 2: Edit the Field Properties / Update the QB Maps button to include the new parameters and values
& "&DBID=" & Dbid()
& "&legrecid=" & 650
& "&legendfid=999"
Replace the 999 with the field id of the legend field you created in step 1.
Step 3: Update the QB_DBID, query, and clist parameters by putting a 1 after them, such as:
& "&QB_DBID1=bbbbbbbbb"
& "&query1={10.EX.Nassau}OR{10.EX.Suffolk}"
& "&clist1=3.21.22.26.27.25.8.11.9.23.$20.28.N16"
Step 4: Update the end of the first line. The original value was something like /QBMaps/default.aspx?
Please update this now so the URL says /QBMaps/qbmaps.aspx?
After you make this change, your map should now look something like this:
