Currently in the Sidebar app when you go to configure a URL parameter you can only select one URL parameter search layer. It would be great to be able to select multiple layers instead of just one and have the same URL parameter apply to all the selected layers.
This would allow using one URL parameter to filter multiple layers.
In my case I need this functionality to be able to grey out the area that is not selected/filtered for but I could also see it being useful for only returning results in a given area.