P: Grid overlay in Geometry / Rotate, Horizontal and Vertical no longer visible

Lightroom Desktop 5.4 running on Windows 10 PRo

Steps to reproduce:-

While editing an image, open the Geometry panel and select the Rotate slider. Note that the grid overlay no longer appears on the image, making it difficult to ensure lines in the image are vertical or horizontal.

Same applies to the Horizontal and Vertical adjustments.

For Rotate a workaround is to use the Crop tool instead (grid works OK).