Bug 587991 - site menu background colors is wrong sometimes [r=mbrubeck]

mobile/chrome/content/browser-ui.js

@@ -1178,22 +1178,25 @@ var PageActions = {
   _updateAttributes: function _updateAttributes() {
     let container = document.getElementById("pageactions-container");
     let visibleNodes = container.querySelectorAll("pageaction:not([hidden=true])");
-    let len = visibleNodes.length;
+    let visibleCount = visibleNodes.length;
 
     let first = null, last = null;
-    for (let i = 0; i < len; i++) {
+    for (let i = 0; i < visibleCount; i++) {
       let node = visibleNodes[i];
       node.removeAttribute("selector");
       // Note: CSS indexes start at one, so even/odd are swapped.
       node.setAttribute("even", (i % 2) ? "true" : "false");
     }
-    if (len >= 1) {
+
+    if (visibleCount >= 1) {
+      visibleNodes[visibleCount - 1].setAttribute("selector", "last-child");
       visibleNodes[0].setAttribute("selector", "first-child");
-      visibleNodes[len-1].setAttribute("selector", "last-child");
     }
-    if (len >= 2) {
+
+    if (visibleCount >= 2) {
+      visibleNodes[visibleCount - 2].setAttribute("selector", "second-last-child");
+      visibleNodes[0].setAttribute("selector", "first-child");
       visibleNodes[1].setAttribute("selector", "second-child");
-      visibleNodes[len-2].setAttribute("selector", "second-last-child");
     }
   }
 };