$context.isVirtual() return wrong result

isVirtual exist in $xwiki (XWiki class) and $context (Context class) but the $xwiki one get directly from the xwiki.cfg file and the $context one just return a internal "virtual" boolean that is never initialised apparently.

I think the best here is to call XWiki.isVirtual() in Context.isVirtual() method.