Default CSS style on draggable elements

Hello,

I created a web page (http://ljouanneau.com/lab/html5/demodragdrop.html) 
to test the new drag'n'drop API of HTML5 (bug 356295). It works, but I 
should have to add the CSS style -moz-user-select:none;, so the drag can 
start immediately. If I don't put this style, I should click a first 
time on the draggable element, and then I can start a drag.

So, is it normal that there isn't a CSS style

   *[draggable=true] { -moz-user-select:none;}

or something like that in the default HTML stylesheet 
layout/style/html.css ?

I ask this question because at this time a web developer should add this 
style on his draggable elements, but since it isn't yet a normalized 
property...

(same issue with XUL http://ljouanneau.com/lab/html5/demodragdrop.xul ;-) )


Laurent