diff --git a/mozilla/content/shared/public/nsCSSKeywordList.h b/mozilla/content/shared/public/nsCSSKeywordList.h
index a968c35ea29..810086b8f82 100644
--- a/mozilla/content/shared/public/nsCSSKeywordList.h
+++ b/mozilla/content/shared/public/nsCSSKeywordList.h
@@ -111,6 +111,7 @@ CSS_KEY(-moz-groupbox, _moz_groupbox)
 CSS_KEY(-moz-gujarati, _moz_gujarati)
 CSS_KEY(-moz-gurmukhi, _moz_gurmukhi)
 CSS_KEY(-moz-hangul-consonant, _moz_hangul_consonant)
+CSS_KEY(-moz-hidden-unscrollable, _moz_hidden_unscrollable)
 CSS_KEY(-moz-hangul, _moz_hangul)
 CSS_KEY(-moz-hyperlinktext, _moz_hyperlinktext)
 CSS_KEY(-moz-info, _moz_info)
diff --git a/mozilla/content/shared/public/nsStyleStruct.h b/mozilla/content/shared/public/nsStyleStruct.h
index d51e9a5600a..34381e87c16 100644
--- a/mozilla/content/shared/public/nsStyleStruct.h
+++ b/mozilla/content/shared/public/nsStyleStruct.h
@@ -84,7 +84,7 @@ nsStyleStructID_Length /* one past the end; length of 0-based list */
 #define NS_RULE_NODE_GC_MARK              0x02000000
 
 #define NS_DEFINE_STATIC_STYLESTRUCTID_ACCESSOR(the_sid) \
-  static const nsStyleStructID GetStyleStructID() {return the_sid;}
+  static nsStyleStructID GetStyleStructID() {return the_sid;}
 
 #define NS_GET_STYLESTRUCTID(type) (type::GetStyleStructID())
 
diff --git a/mozilla/content/shared/src/nsCSSProps.cpp b/mozilla/content/shared/src/nsCSSProps.cpp
index 6f012ef879b..b14a272cbfc 100644
--- a/mozilla/content/shared/src/nsCSSProps.cpp
+++ b/mozilla/content/shared/src/nsCSSProps.cpp
@@ -625,11 +625,12 @@ const PRInt32 nsCSSProps::kOutlineColorKTable[] = {
 
 const PRInt32 nsCSSProps::kOverflowKTable[] = {
   eCSSKeyword_visible, NS_STYLE_OVERFLOW_VISIBLE,
-  eCSSKeyword_hidden, NS_STYLE_OVERFLOW_HIDDEN,
+  eCSSKeyword_hidden, NS_STYLE_OVERFLOW_SCROLLBARS_NONE,
   eCSSKeyword_scroll, NS_STYLE_OVERFLOW_SCROLL,
   eCSSKeyword__moz_scrollbars_none, NS_STYLE_OVERFLOW_SCROLLBARS_NONE,
   eCSSKeyword__moz_scrollbars_horizontal, NS_STYLE_OVERFLOW_SCROLLBARS_HORIZONTAL,
   eCSSKeyword__moz_scrollbars_vertical, NS_STYLE_OVERFLOW_SCROLLBARS_VERTICAL,
+  eCSSKeyword__moz_hidden_unscrollable, NS_STYLE_OVERFLOW_HIDDEN,
   -1,-1
 };
 
diff --git a/mozilla/extensions/editor/cascades/resources/content/EdCssProps.css b/mozilla/extensions/editor/cascades/resources/content/EdCssProps.css
index d86ec4a644e..e7d7c0e0c62 100644
--- a/mozilla/extensions/editor/cascades/resources/content/EdCssProps.css
+++ b/mozilla/extensions/editor/cascades/resources/content/EdCssProps.css
@@ -51,7 +51,7 @@ html|p#brownFoxLabel {
   border: 1px solid black;
   margin: 0px;
   padding: 2px;
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   height: 70px;
   max-height: 70px;
   line-height: 70px;
diff --git a/mozilla/layout/forms/resources/content/xbl-forms.css b/mozilla/layout/forms/resources/content/xbl-forms.css
index 4a320ae0451..eaf0992a6f6 100644
--- a/mozilla/layout/forms/resources/content/xbl-forms.css
+++ b/mozilla/layout/forms/resources/content/xbl-forms.css
@@ -226,7 +226,7 @@ textarea > scrollbar {
 }
 
 *|*::-moz-singleline-textcontrol-frame {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   white-space: nowrap;
   background-color: inherit;
   text-align: inherit;
diff --git a/mozilla/layout/generic/nsBlockReflowContext.cpp b/mozilla/layout/generic/nsBlockReflowContext.cpp
index 8587f10ebb4..bb467d5f9f4 100644
--- a/mozilla/layout/generic/nsBlockReflowContext.cpp
+++ b/mozilla/layout/generic/nsBlockReflowContext.cpp
@@ -657,8 +657,8 @@ nsBlockReflowContext::PlaceBlock(const nsHTMLReflowState& aReflowState,
   // XXXldb What should really matter is whether there exist non-
   // empty frames in the block (with appropriate whitespace munging).
   // Consider the case where we clip off the overflow with
-  // 'overflow: hidden' (which doesn't currently affect mOverflowArea,
-  // but probably should.
+  // 'overflow: -moz-hidden-unscrollable' (which doesn't currently
+  // affect mOverflowArea, but probably should.
   if ((0 == mMetrics.height) && (0 == mMetrics.mOverflowArea.height)) 
   {
     // Collapse the bottom margin with the top margin that was already
diff --git a/mozilla/layout/html/base/src/nsBlockReflowContext.cpp b/mozilla/layout/html/base/src/nsBlockReflowContext.cpp
index 8587f10ebb4..bb467d5f9f4 100644
--- a/mozilla/layout/html/base/src/nsBlockReflowContext.cpp
+++ b/mozilla/layout/html/base/src/nsBlockReflowContext.cpp
@@ -657,8 +657,8 @@ nsBlockReflowContext::PlaceBlock(const nsHTMLReflowState& aReflowState,
   // XXXldb What should really matter is whether there exist non-
   // empty frames in the block (with appropriate whitespace munging).
   // Consider the case where we clip off the overflow with
-  // 'overflow: hidden' (which doesn't currently affect mOverflowArea,
-  // but probably should.
+  // 'overflow: -moz-hidden-unscrollable' (which doesn't currently
+  // affect mOverflowArea, but probably should.
   if ((0 == mMetrics.height) && (0 == mMetrics.mOverflowArea.height)) 
   {
     // Collapse the bottom margin with the top margin that was already
diff --git a/mozilla/layout/html/document/src/forms.css b/mozilla/layout/html/document/src/forms.css
index 3d20ee63c28..228001397c6 100644
--- a/mozilla/layout/html/document/src/forms.css
+++ b/mozilla/layout/html/document/src/forms.css
@@ -120,7 +120,7 @@ textarea > scrollbar {
 }
 
 *|*::-moz-singleline-textcontrol-frame {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   white-space: nowrap;
   background-color: inherit;
   text-align: inherit;
@@ -185,7 +185,7 @@ select::-moz-dummy-option {
 }
 
 *|*::-moz-display-comboboxcontrol-frame {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   /* This top/bottom padding plus the combobox top/bottom border need to
      add up to the top/bottom borderpadding of text inputs and buttons */ 
   padding: 1px 0 1px 4px;
diff --git a/mozilla/layout/html/document/src/html.css b/mozilla/layout/html/document/src/html.css
index ef79af35b3a..957119ac633 100644
--- a/mozilla/layout/html/document/src/html.css
+++ b/mozilla/layout/html/document/src/html.css
@@ -392,7 +392,7 @@ object, embed, applet {
 
 frameset {
   display: block ! important;
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
 }
 
 frame {
diff --git a/mozilla/layout/html/forms/resources/content/xbl-forms.css b/mozilla/layout/html/forms/resources/content/xbl-forms.css
index 4a320ae0451..eaf0992a6f6 100644
--- a/mozilla/layout/html/forms/resources/content/xbl-forms.css
+++ b/mozilla/layout/html/forms/resources/content/xbl-forms.css
@@ -226,7 +226,7 @@ textarea > scrollbar {
 }
 
 *|*::-moz-singleline-textcontrol-frame {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   white-space: nowrap;
   background-color: inherit;
   text-align: inherit;
diff --git a/mozilla/layout/style/forms.css b/mozilla/layout/style/forms.css
index 3d20ee63c28..228001397c6 100644
--- a/mozilla/layout/style/forms.css
+++ b/mozilla/layout/style/forms.css
@@ -120,7 +120,7 @@ textarea > scrollbar {
 }
 
 *|*::-moz-singleline-textcontrol-frame {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   white-space: nowrap;
   background-color: inherit;
   text-align: inherit;
@@ -185,7 +185,7 @@ select::-moz-dummy-option {
 }
 
 *|*::-moz-display-comboboxcontrol-frame {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   /* This top/bottom padding plus the combobox top/bottom border need to
      add up to the top/bottom borderpadding of text inputs and buttons */ 
   padding: 1px 0 1px 4px;
diff --git a/mozilla/layout/style/html.css b/mozilla/layout/style/html.css
index ef79af35b3a..957119ac633 100644
--- a/mozilla/layout/style/html.css
+++ b/mozilla/layout/style/html.css
@@ -392,7 +392,7 @@ object, embed, applet {
 
 frameset {
   display: block ! important;
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
 }
 
 frame {
diff --git a/mozilla/layout/style/nsCSSKeywordList.h b/mozilla/layout/style/nsCSSKeywordList.h
index a968c35ea29..810086b8f82 100644
--- a/mozilla/layout/style/nsCSSKeywordList.h
+++ b/mozilla/layout/style/nsCSSKeywordList.h
@@ -111,6 +111,7 @@ CSS_KEY(-moz-groupbox, _moz_groupbox)
 CSS_KEY(-moz-gujarati, _moz_gujarati)
 CSS_KEY(-moz-gurmukhi, _moz_gurmukhi)
 CSS_KEY(-moz-hangul-consonant, _moz_hangul_consonant)
+CSS_KEY(-moz-hidden-unscrollable, _moz_hidden_unscrollable)
 CSS_KEY(-moz-hangul, _moz_hangul)
 CSS_KEY(-moz-hyperlinktext, _moz_hyperlinktext)
 CSS_KEY(-moz-info, _moz_info)
diff --git a/mozilla/layout/style/nsCSSProps.cpp b/mozilla/layout/style/nsCSSProps.cpp
index 6f012ef879b..b14a272cbfc 100644
--- a/mozilla/layout/style/nsCSSProps.cpp
+++ b/mozilla/layout/style/nsCSSProps.cpp
@@ -625,11 +625,12 @@ const PRInt32 nsCSSProps::kOutlineColorKTable[] = {
 
 const PRInt32 nsCSSProps::kOverflowKTable[] = {
   eCSSKeyword_visible, NS_STYLE_OVERFLOW_VISIBLE,
-  eCSSKeyword_hidden, NS_STYLE_OVERFLOW_HIDDEN,
+  eCSSKeyword_hidden, NS_STYLE_OVERFLOW_SCROLLBARS_NONE,
   eCSSKeyword_scroll, NS_STYLE_OVERFLOW_SCROLL,
   eCSSKeyword__moz_scrollbars_none, NS_STYLE_OVERFLOW_SCROLLBARS_NONE,
   eCSSKeyword__moz_scrollbars_horizontal, NS_STYLE_OVERFLOW_SCROLLBARS_HORIZONTAL,
   eCSSKeyword__moz_scrollbars_vertical, NS_STYLE_OVERFLOW_SCROLLBARS_VERTICAL,
+  eCSSKeyword__moz_hidden_unscrollable, NS_STYLE_OVERFLOW_HIDDEN,
   -1,-1
 };
 
diff --git a/mozilla/layout/style/nsStyleStruct.h b/mozilla/layout/style/nsStyleStruct.h
index d51e9a5600a..34381e87c16 100644
--- a/mozilla/layout/style/nsStyleStruct.h
+++ b/mozilla/layout/style/nsStyleStruct.h
@@ -84,7 +84,7 @@ nsStyleStructID_Length /* one past the end; length of 0-based list */
 #define NS_RULE_NODE_GC_MARK              0x02000000
 
 #define NS_DEFINE_STATIC_STYLESTRUCTID_ACCESSOR(the_sid) \
-  static const nsStyleStructID GetStyleStructID() {return the_sid;}
+  static nsStyleStructID GetStyleStructID() {return the_sid;}
 
 #define NS_GET_STYLESTRUCTID(type) (type::GetStyleStructID())
 
diff --git a/mozilla/themes/classic/editor/EditorDialog.css b/mozilla/themes/classic/editor/EditorDialog.css
index 00f676e598c..1c7b7e3a7a8 100644
--- a/mozilla/themes/classic/editor/EditorDialog.css
+++ b/mozilla/themes/classic/editor/EditorDialog.css
@@ -277,7 +277,7 @@ tree.list {
   max-height : 52px;
   min-height : 52px;
   margin     : 6px 5px 6px 5px;
-  overflow   : hidden;
+  overflow   : -moz-hidden-unscrollable;
 }
 
 #preview-image-holder {
diff --git a/mozilla/themes/classic/editor/editor.css b/mozilla/themes/classic/editor/editor.css
index d205a6e4640..4679422df8b 100644
--- a/mozilla/themes/classic/editor/editor.css
+++ b/mozilla/themes/classic/editor/editor.css
@@ -67,7 +67,7 @@
 
 #structToolbar {
   min-width: 1px;
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
 }
 
 #structSpacer {
diff --git a/mozilla/themes/modern/editor/EditorDialog.css b/mozilla/themes/modern/editor/EditorDialog.css
index 6a1d3b8d366..c4591fadfb6 100644
--- a/mozilla/themes/modern/editor/EditorDialog.css
+++ b/mozilla/themes/modern/editor/EditorDialog.css
@@ -276,7 +276,7 @@ tree.list {
   min-height: 52px;
   max-width: 82px;
   max-height: 52px;
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
 }
 
 #preview-image-holder {
diff --git a/mozilla/themes/modern/editor/editor.css b/mozilla/themes/modern/editor/editor.css
index 7f823c8ee51..79517510a7b 100644
--- a/mozilla/themes/modern/editor/editor.css
+++ b/mozilla/themes/modern/editor/editor.css
@@ -67,7 +67,7 @@
 
 #structToolbar {
   min-width: 1px;
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
 }
 
 #structSpacer {
diff --git a/mozilla/toolkit/content/xul.css b/mozilla/toolkit/content/xul.css
index 4b5e11ea40c..ee43c1fb3b1 100644
--- a/mozilla/toolkit/content/xul.css
+++ b/mozilla/toolkit/content/xul.css
@@ -85,7 +85,7 @@ radio {
 
 window, 
 page {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   -moz-box-orient: vertical;
 }
 
diff --git a/mozilla/xpfe/global/resources/content/xul.css b/mozilla/xpfe/global/resources/content/xul.css
index 371ae5f7398..14957c14439 100644
--- a/mozilla/xpfe/global/resources/content/xul.css
+++ b/mozilla/xpfe/global/resources/content/xul.css
@@ -98,7 +98,7 @@ radio {
 
 window, 
 page {
-  overflow: hidden;
+  overflow: -moz-hidden-unscrollable;
   -moz-box-orient: vertical;
 }