Beta dashboard filters

[svickers]

I noticed when adding filters to a beta dashboard that you are only allowed to select fields from explores that currently exist in vizs on the dashboard. We frequently use small purpose-built tables to make filter loading much quicker or handle certain business rules and then map the values to the appropriate fields in each viz. Is this planned to be supported like the current dashboards, or is this the new normal we will have to figure out how to work around?