On a XEM environment where the skin is in a different wiki than the current wiki, the skin extension's properties that point to css files cannot be used.
$xwiki.getSkinFile() returns an invalid url when in an XEM environment where the skin document is in a different wiki than the current wiki.
The code behind the function from XWiki.java
is that it assumes that the skin resides in the current wiki.
This should be changed to
so that the class reference point to the wiki where the skin is.