Lightroom Classic: Cropping in LrC with Two Monitors

In previous versions of Lightroom, you could zoom in on an image on a second monitor whist cropping on the main screen and the crop would happen in 'real-time' on the zoomed in second monitor. This allowed you to be much more accurate when cropping to very exact levels. 
Now, when you try this the second monitor does nothing until you release the mouse and the image crops to the point selected. ie you don't get to see it actually happening whist zoomed in.

Does anyone know how to restore this functionality? And if it can't, why was the ability removed?
To be accurate on a crop, now necessitates going over to PS...