Bug 408904 Fix crash regression from bug 384874 r=Enn sr=bz a=beltzner

layout/xul/base/src/nsSprocketLayout.cpp

@@ -782,8 +782,10 @@ nsSprocketLayout::PopulateBoxSizes(nsIBox* aBox, nsBoxLayoutState& aState, nsBox
 
   while(child)
   {
-    while (currentBox && currentBox->bogus)
+    while (currentBox && currentBox->bogus) {
+      last = currentBox;
       currentBox = currentBox->next;
+    }
     ++childCount;
     nsSize pref(0,0);
     nsSize min(0,0);