true false true false An xbl:content must be a descendent of an xbl:template element and must not be a descendent of an xbl:content element. true false true false An xbl:inherited must be a descendent of an xbl:template element. An xbl:attr must be a descendent of an xbl:template element. An xbl:pseudo must be a descendent of an xbl:template element. value choices label repeat-item icon capture target bubble default-action true false stop continue cancel perform standard left right numpad