dojox.widget.dialog: disable close button opacity animation

Question

I am nearly happy with my dialog widget now, only that there is a built-in behavior of the close button fading in and out with mouseover/out interaction. I have found no way to disable this feature such that the close button remains at full opacity anytime the dialog is open.

Here's roughly the code I'm working from:

var d = new dojox.widget.Dialog({modal:true,sizeMethod:"chain",closable:true});
d.startup();
d.attr('content', /*html content*/); 
d.attr('dimensions',[/*width*/, /*height*/ ]).show();

There's much logic that I'm omitting here for brevity, but this should be all that is specifically pertinent to the way I am constructing the dialog.

Many Thanks.