fixed only affects one level of scrollable ancestors.

lib/widget.js

@@ -2650,6 +2650,7 @@ Element.prototype._getCoords = function(get) {
     , yl = yi + this._getHeight(get)
     , base = this.childBase || 0
     , el = this
+    , fixed = this.fixed
     , coords
     , v
     , notop
@@ -2666,14 +2667,20 @@ Element.prototype._getCoords = function(get) {
 
   // Find a scrollable ancestor if we have one.
   while (el = el.parent) {
-    if (el.scrollable) break;
+    if (el.scrollable) {
+      if (fixed) {
+        fixed = false;
+        continue;
+      }
+      break;
+    }
   }
 
   // Check to make sure we're visible and
   // inside of the visible scroll area.
   // NOTE: Lists have a property where only
   // the list items are obfuscated.
-  if (el && !this.fixed) {
+  if (el) {
     ppos = get
       ? this.parent.lpos
       : this.parent._getCoords();