After working in PL 5.3.1 for a while in two folders, I minimized the window for about a day, then returned to it, selected the first folder I was working in, made a virtual copy of one of the TIFF images, selected that VC, then selected Local Adjustments. No overlays appeared in the viewer. I could right-click and get the brush menu, select a control point, and place it - but the control point, equalizer, etc. were all invisible. I could press M to show the mask - that worked - and could use the Del key to remove the control point, but that’s all. Switching images didn’t help. I had to shut down and restart PhotoLab to get Local Adjustments working again.
Also, when PL shut down, the mouse froze for about 20 seconds.