Brand portal - Need to be able to enter the Filter rail when looking at a Collection.

I go to the Collections page and click into a collection I've previously created.

I get the assets displayed, but I'm then not able to open the left hand search panel to filter the collection

From the Files section - if I go to filters and select the saved search (collection) - it obviously does allow me filter them.

I want to be able to filter the display of a Collection.