STORES: How do I assign listings to Store Category in Bulk?

[stoneledge]

I'm new to Stores.

I want to add many listings to a Store Category at one time, rather than go into each listing.

In Bulk Edit Listings mode, I've added Store Category to the Fields/Columns.  

In Edit mode the Bulk Editor won't  let me  change the values in the Store Category field.   They all still say "other" and are greyed out.    Bulk Editor will let me edit other fields like Quantity Available and Price.  

So how can I assign a large number of Listed Items to a Store Category all at once?