Yep, Histogram cut for me too. Also for now at least one wrong localization to German. But forgot which. My problems with migration have already their own long post here. But presets, modules and the rest was fine. Changing the default preset was quickly done. Will try now the new build.
My custom presets (both those kept in main folder and in a subfolder) made it across safely on OS X 10.14.6. Good point about the histograms though. Some work to do there. Making the histogram a bit taller wouldn’t hurt.
You can stretch the histogram height by grabbing the bottom of it with a double arrow cursor (at least in the Windows version.). You have to play with positioning a bit for the cursor to appear.
I am also seeing the “chopped” histogram as well on both macOS Catalina and in Windows10/2004.
I am seeing some other oddities but need to work with PL4 a bit longer to nail down consistent cause/effect (image thumbnail selection oddities, crop window coming up as portrait aspect ratio for images in a landscape aspect ratio, etc.). None of them are serious show stoppers but sometimes annoying. These are things that weren’t occurring in PL3.