There's something odd happening when one tries to add a 'filter' property (e.g. filter:url(#filterid) ) to a style attribute, on a XML Editor dialog. The filter object is found (if it exists) and correctly loaded into the SPStyle object but in the end, for some reason, the 'filter' property is simply discarded and ends up not being set (try it yourselves if this sounds confusing). I've been debugging style.cpp and related methods exhaustively and can't understand why this happens, is there something that needs to be enabled somewhere else? Can someone more enlightened on this subject please provide some hints here?