--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -1127,16 +1127,17 @@ GK_ATOM(scrollbar, "scrollbar")
 GK_ATOM(scrollbarbutton, "scrollbarbutton")
 GK_ATOM(scrollbarDownBottom, "scrollbar-down-bottom")
 GK_ATOM(scrollbarDownTop, "scrollbar-down-top")
 GK_ATOM(scrollbarUpBottom, "scrollbar-up-bottom")
 GK_ATOM(scrollbarUpTop, "scrollbar-up-top")
 GK_ATOM(scrollbox, "scrollbox")
 GK_ATOM(scrollcorner, "scrollcorner")
 GK_ATOM(scrolling, "scrolling")
+GK_ATOM(scrollPosition, "scroll-position")
 GK_ATOM(section, "section")
 GK_ATOM(select, "select")
 GK_ATOM(selectable, "selectable")
 GK_ATOM(selected, "selected")
 GK_ATOM(selectedIndex, "selectedIndex")
 GK_ATOM(selectedindex, "selectedindex")
 GK_ATOM(self, "self")
 GK_ATOM(seltype, "seltype")