I hope you become a contributor.
The .ijs files you mention are provided by PhpLayersMenu, a 3rd party library included in TikiWiki. Unless we want to end up with our own branch/fork of PLM, they should change it and we include that. There has not been any PLM releases in while though...
What are the visible bugs caused by this? Some people report bugs and others say "works for me". Maybe this would permit to understand and solve certain bugs.