Again something similar to what you want is all possible using the filter technique used in the demo app if you really need to do that.
The dashboard would have two windows, one filter, the other material info.
You can also control the dropdown list order by using SORT, ORDERBY, etc, perhaps together with ‘master’ tables such as COLROS, CATEGORIES, SUPLLIERS with order by column (if not just alphabetically).
At the risk of offending AppSheet enthusiasts, I have used Data Studio to provide a material search solution which is much more strait forward if all you want is just filtering.