diff --git a/mozilla/content/base/public/nsIContent.h b/mozilla/content/base/public/nsIContent.h
index 506ba4a5ae7..8d4cb7d843f 100644
--- a/mozilla/content/base/public/nsIContent.h
+++ b/mozilla/content/base/public/nsIContent.h
@@ -665,6 +665,9 @@ public:
   // Tab focus model bit field:
   static PRInt32 sTabFocusModel;
 
+  // accessibility.tabfocus_applies_to_xul pref - if it is set to true,
+  // the tabfocus bit field applies to xul elements.
+  static PRBool sTabFocusModelAppliesToXUL;
 
 protected:
   typedef PRWord PtrBits;
diff --git a/mozilla/content/base/src/nsGenericElement.cpp b/mozilla/content/base/src/nsGenericElement.cpp
index bd71ffc1a44..39c24ae3683 100644
--- a/mozilla/content/base/src/nsGenericElement.cpp
+++ b/mozilla/content/base/src/nsGenericElement.cpp
@@ -125,6 +125,7 @@ DebugListContentTree(nsIContent* aElement)
 PLDHashTable nsGenericElement::sRangeListsHash;
 PLDHashTable nsGenericElement::sEventListenerManagersHash;
 PRInt32 nsIContent::sTabFocusModel = eTabFocus_any;
+PRBool nsIContent::sTabFocusModelAppliesToXUL = PR_FALSE;
 //----------------------------------------------------------------------
 
 nsChildContentList::nsChildContentList(nsIContent *aContent)
diff --git a/mozilla/content/events/src/nsEventStateManager.cpp b/mozilla/content/events/src/nsEventStateManager.cpp
index 0eba014f2cb..a00364a5155 100644
--- a/mozilla/content/events/src/nsEventStateManager.cpp
+++ b/mozilla/content/events/src/nsEventStateManager.cpp
@@ -226,9 +226,14 @@ nsEventStateManager::Init()
       sGeneralAccesskeyModifier =
         nsContentUtils::GetIntPref("ui.key.generalAccessKey",
                                    sGeneralAccesskeyModifier);
+
+      nsIContent::sTabFocusModelAppliesToXUL =
+        nsContentUtils::GetBoolPref("accessibility.tabfocus_applies_to_xul",
+                                    nsIContent::sTabFocusModelAppliesToXUL);
     }
     prefBranch->AddObserver("accessibility.accesskeycausesactivation", this, PR_TRUE);
     prefBranch->AddObserver("accessibility.browsewithcaret", this, PR_TRUE);
+    prefBranch->AddObserver("accessibility.tabfocus_applies_to_xul", this, PR_TRUE);
     prefBranch->AddObserver("nglayout.events.dispatchLeftClickOnly", this, PR_TRUE);
     prefBranch->AddObserver("ui.key.generalAccessKey", this, PR_TRUE);
 #if 0
@@ -305,6 +310,7 @@ nsEventStateManager::Shutdown()
   if (prefBranch) {
     prefBranch->RemoveObserver("accessibility.accesskeycausesactivation", this);
     prefBranch->RemoveObserver("accessibility.browsewithcaret", this);
+    prefBranch->RemoveObserver("accessibility.tabfocus_applies_to_xul", this);
     prefBranch->RemoveObserver("nglayout.events.dispatchLeftClickOnly", this);
     prefBranch->RemoveObserver("ui.key.generalAccessKey", this);
 #if 0
@@ -347,6 +353,10 @@ nsEventStateManager::Observe(nsISupports *aSubject,
                                     sKeyCausesActivation);
     } else if (data.EqualsLiteral("accessibility.browsewithcaret")) {
       ResetBrowseWithCaret();
+    } else if (data.EqualsLiteral("accessibility.tabfocus_applies_to_xul")) {
+      nsIContent::sTabFocusModelAppliesToXUL =
+        nsContentUtils::GetBoolPref("accessibility.tabfocus_applies_to_xul",
+                                    nsIContent::sTabFocusModelAppliesToXUL);
     } else if (data.EqualsLiteral("nglayout.events.dispatchLeftClickOnly")) {
       sLeftClickOnly =
         nsContentUtils::GetBoolPref("nglayout.events.dispatchLeftClickOnly",
diff --git a/mozilla/content/xul/content/src/nsXULElement.cpp b/mozilla/content/xul/content/src/nsXULElement.cpp
index a69fd322f5a..994032f1335 100644
--- a/mozilla/content/xul/content/src/nsXULElement.cpp
+++ b/mozilla/content/xul/content/src/nsXULElement.cpp
@@ -686,6 +686,16 @@ nsXULElement::IsFocusable(PRInt32 *aTabIndex)
       // If attribute not set, will use default value passed in
       xulControl->GetTabIndex(&tabIndex);
     }
+    if (tabIndex != -1 && sTabFocusModelAppliesToXUL &&
+        !(sTabFocusModel & eTabFocus_formElementsMask)) {
+      // By default, the tab focus model doesn't apply to xul element on any system but OS X.
+      // on OS X we're following it for UI elements (XUL) as sTabFocusModel is based on
+      // "Full Keyboard Access" system setting (see mac/nsILookAndFeel).
+      // both textboxes and list elements (i.e. trees and list) should always be focusable
+      // (textboxes are handled as html:input)
+      if (!mNodeInfo->Equals(nsXULAtoms::tree) && !mNodeInfo->Equals(nsXULAtoms::listbox))
+        tabIndex = -1; 
+    }
   }
 
   if (aTabIndex) {
diff --git a/mozilla/modules/libpref/src/init/all.js b/mozilla/modules/libpref/src/init/all.js
index 93df2479ddb..299bb8bbc07 100644
--- a/mozilla/modules/libpref/src/init/all.js
+++ b/mozilla/modules/libpref/src/init/all.js
@@ -107,6 +107,10 @@ pref("accessibility.warn_on_browsewithcaret", true);
 // On OS X, we use Full Keyboard Access system preference,
 // unless accessibility.tabfocus is set by the user.
 pref("accessibility.tabfocus", 7);
+pref("accessibility.tabfocus_applies_to_xul", false);
+#else
+// Only on mac tabfocus is expected to handle UI widgets as well as web content
+pref("accessibility.tabfocus_applies_to_xul", true);
 #endif
 
 pref("accessibility.usetexttospeech", "");