I just discovered metadata navigation while setting up an Asset Library to store my company's media. It's really handy, given that I had previously just been applying filters directly from the columns. My only issue is that I can't find a way to allow a key filter field to allow multiple selections. For example, if I have a column called "Vendor" that lists the different vendors of software, I want to be able to select Vendor 1 and Vendor 2 when using the key filters, but I am only able to select one value.
When I use the dropdown next to a column name, I can filter by multiple values and see only Vendor 1 and Vendor 2. Am I missing something? Is there a way to allow multiple selections for a key filter in the managed metadata navigation area?