While using Assistant, I noticed that I couldn't just hover over linked sources and click their titles. Instead, I have to manually click the number first, and only then can I click the link. This feels unintuitive.

I assume this could be a minor change and a QoL improvement.
The fix would be to give some extra time before fading the box away and, if needed, detect whether the mouse is hovering over the box. If it is, keep it visible.