You need to define a specific folder for B4X additional libraries with the following structure.
Additional libraries for B4A, B4i, B4J or B4R must be saved in their specific subfolder.
B4Xlib files must be saved in the B4X subfolder.
You can add a B4XlibXMLFiles folder for xml hlep files for B4Xlibs.
That's not the good way!
If you set the AdditionalLibraries folder as C:\AdditionalLibraries with the subfolders as explained in post #3 then set the AdditionalLibraries folder in the IDE as C:\AdditionalLibraries.
The IDE will automatically use the correct subfolder.
If you currently have an AdditionalLibraries folder for B4i, then move all files to C:\AdditionalLibraries\B4i.
The drawback with your solution is that the b4xlib will only be seen by B4i and not from B4A and B4J.