This is all I see when the mouse is hovered over the little grey page icon [which I think is a ridiculous thing to be expected to do]. A tiny pop-up that says 'post', and the thread link string at the bottom.If you hover your mouse over the 'red or gray page' icon at the start of the message a blue bar at the bottom of your screen shows the post #.
We need the Post # displayed where it can be seen, not thru some secret hocus-pocus. It's simple customer service. Why 'new' versions of things are ALWAYS predictably worse than the prior version should be an EXTREME embarrassment to those responsible for their poor designs and further for their lack of ability to correct things in a timely fashion.