Add a 2nd BROWSER as a floating tool or as an optional add-on to Capture One Studio Client Viewers.
Often, photographers or clients are browsing through images on an external monitor (Eizo, Studio Display, etc.) and, when using a Client Viewer, they scroll forwards or backwards through the photographs one by one without knowing where they are in relation to the entire set of images.
I believe this would be a significant improvement in usability for clients.