It works for me, so there must be something different about your setup. Is it just your files you cannot see, or do you not get any library items at all?
What other addons do you install? Have you expanded the partition? Does a source scan seem to work? Are all the library items ticked?
I will describe my installation.
on an empty card I installed the version runeaudio 0.5b.
I launched the raspberry pi 3b.
I went to the dev mode, dev mode = on.
In mode dev: "install rernaddons"
dev mode = off
cleaned the firefox cache
Then i went to "menu", "addons", "RuneUI enhancement", "Install".
and after i have the new skin.
i can click on all the menu, taskbar buttons, everithing works except the taskbar button "library".
nothing happens, not even the color change showing that we clicked on it.
in the libray items, all is ticked.
I have not installed anything, or even configured my i2s sound card and i am on ethernet for the moment.
After a new clear cache, reboot, uninstall, change mode dev to on, re-install runeUI enhancement, always the same problem.
I gave up and came back to the original RuneUI.
I noticed that during the installation of runeUI enhancement, he tries to change the midori config he can not find. This questions me because midori has been replaced by chromium on this version of runeaudio.
Maybe it will work on a upcoming update.
In any case, I thank all those who tried to help me.