--- a/dom/base/nsGkAtomList.h
+++ b/dom/base/nsGkAtomList.h
@@ -2209,16 +2209,17 @@ GK_ATOM(IMETxnName, "IME")
 GK_ATOM(DeleteTxnName, "Deleting")
 
 // Font families
 GK_ATOM(serif, "serif")
 GK_ATOM(sans_serif, "sans-serif")
 GK_ATOM(cursive, "cursive")
 GK_ATOM(fantasy, "fantasy")
 GK_ATOM(monospace, "monospace")
+GK_ATOM(mozfixed, "-moz-fixed")
 
 // IPC stuff
 GK_ATOM(Remote, "remote")
 GK_ATOM(RemoteId, "_remote_id")
 GK_ATOM(RemoteType, "remoteType")
 GK_ATOM(DisplayPort, "_displayport")
 GK_ATOM(DisplayPortMargins, "_displayportmargins")
 GK_ATOM(DisplayPortBase, "_displayportbase")