LauncherFolders (http://unity-folders.exceptionfound.com , https://itsfoss.com/group-apps-unity-launcher-launcherfolders) is a great extension to the unity launcher, in being lightweight abd shipping a lot of bang when it only comes to set up containers organizing your apps. However, obviously the code has been crafted back in the Ubuntu 14.04 era, leaving open issues for installation on more modern Ubuntu releases.
First of all, the official ppa (ppa:asukhovatkin/unity-launcher-folders) will no longer register successfully for security reasons such that one has to ressort back to the original deb installation medium (http://unity-folders.exceptionfound.com/unity-launcher-folders_1.0.3_all.deb).
The next fixes, run the app from the console to see the error messages, are documented in (https://askubuntu.com/questions/934916/ubuntu-launcher-folder-not-working) and (https://ubuntuforums.org/showthread.php?t=2325175 , comment #5):
sudo apt install python-gobject python-pil gksudo gedit /usr/lib/python2.7/dist-packages/unity_launcher_folders/generateIcon.py #17 change: "import Image" -> "from PIL import Image"
Getting this far, the app itself comes up and is operable as expected. Pity is but, that the folder pane does not show up when clicking the generated launcher item (though it worked in the preview mode). The launcher item itself is nothing more than some .desktop file in (
~/.local/share/applications/Browser.desktop). On inspection, we have this exec entry:
Giving it another console output run reveals another missing python dependency: