Lightroom cropping tool no longer shows popular size when adjusting size box.

To build on Just Shoot Me's reply, here's more detail:

Prior to LR 8.1, LR would incorrectly display a crop ratio label that was near but not exactly the same as the actual crop ratio. So as you dragged the boundary of the crop tool, there would be a number of pixel positions that would all display the same crop ratio label, even though their exact ratio was different. Now LR will display a crop ratio label only if exporting the cropped photo would produce dimensions that are exactly that ratio (within half a pixel).

For example, consider a 6000 x 4000 photo, with ratio 1.5. Initially, the old LR would display the label "Original" (1.5).  As you start dragging the right crop boundary from 6000 to 5999 to 5998 ... 5980, LR would keep displaying "Original", even though the ratio of 5980 x 4000 is 1.495, not 1.5.   As you dragged the boundary to pixel 5200, the exact ratio becomes 5200 / 4000 = 1.3.  But LR would display the ratio as 11 x 8.5 (a ratio of ~ 1.294).

This causes two significant problems.

First, there was no way for someone to create a custom crop ratio of 13 x 10 -- LR would automatically change it to 11 x 8.5.

Second, an exported photo could have dimensions that are much more than half a pixel away from the displayed crop ratio.  For example, suppose you used the crop tool to drag the crop boundary so that the pixel dimensions were 5200 x 4000 (1.3). LR would display the ratio as 11 x 8.5.  But when you exported that photo, it wouldn't export with 11 x 8.5 (5176 x 4000), it would export as 1.3 (5200 x 4000), an error of 24 pixels from the displayed 11 x 8.5 crop ratio.

Lots of people complained about these problems: Lightroom: I can't add (certain) custom crop ratios | Photoshop Family Customer Community . Adobe finally fixed it in LR 8.1.

As Just Shoot Me pointed out, if you want an exact crop ratio, select it in the crop tool or create a new custom aspect ratio.