Prior to installing B4R v4beta I did delete "c:\Users\<User>\Documents\B4X\AdditionalLibraries\B4R\". However, I forgot to uninstall B4R v3.9 before installing B4R v4beta. I did uninstall B4R v3.9 afterwards, using its uninstall.exe. Still, the Libraries Manager in B4R v4beta lists a few 'additional' ghost libraries (see screenshot). How can I get rid of those?
Solved: I found a folder "C:\Users\<User>\AppData\Roaming\Anywhere Software\B4R" that the uninstaller had left - probably intentionally. The files in this folder seem to contain all kinds of useful settings, also about installed libraries. As a QND solution, I removed the entire folder. The next installation run was 'from scratch'.