diff --git a/gfx/public/nsITheme.h b/gfx/public/nsITheme.h
index cf3ca7448712..b5455d884d01 100644
--- a/gfx/public/nsITheme.h
+++ b/gfx/public/nsITheme.h
@@ -57,14 +57,20 @@ class nsIContent;
 class nsIAtom;
 
 // IID for the nsITheme interface
-// {df8baf21-5ea7-49eb-a2bc-f2fd4a9fd896}
+// {f5eb2e02-ed3f-4340-82fc-22f55bb556f9}
 #define NS_ITHEME_IID     \
-{ 0xdf8baf21, 0x5ea7, 0x49eb, { 0xa2, 0xbc, 0xf2, 0xfd, 0x4a, 0x9f, 0xd8, 0x96 } }
+{ 0xf5eb2e02, 0xed3f, 0x4340, { 0x82, 0xfc, 0x22, 0xf5, 0x5b, 0xb5, 0x56, 0xf9 } }
 
 // {D930E29B-6909-44e5-AB4B-AF10D6923705}
 #define NS_THEMERENDERER_CID \
 { 0xd930e29b, 0x6909, 0x44e5, { 0xab, 0x4b, 0xaf, 0x10, 0xd6, 0x92, 0x37, 0x5 } }
 
+enum nsTransparencyMode {
+  eTransparencyOpaque = 0,  // Fully opaque
+  eTransparencyTransparent, // Parts of the window may be transparent
+  eTransparencyGlass        // Transparent parts of the window have Vista AeroGlass effect applied
+};
+
 /**
  * nsITheme is a service that provides platform-specific native
  * rendering for widgets.  In other words, it provides the necessary
@@ -133,6 +139,8 @@ public:
                                   nsSize* aResult,
                                   PRBool* aIsOverridable)=0;
 
+  virtual nsTransparencyMode GetWidgetTransparency(PRUint8 aWidgetType)=0;
+
   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, PRUint8 aWidgetType, 
                                 nsIAtom* aAttribute, PRBool* aShouldRepaint)=0;
 
diff --git a/layout/base/nsLayoutUtils.cpp b/layout/base/nsLayoutUtils.cpp
index a94b7d37040b..7b1a3447da5d 100644
--- a/layout/base/nsLayoutUtils.cpp
+++ b/layout/base/nsLayoutUtils.cpp
@@ -2948,8 +2948,9 @@ nsLayoutUtils::GetFrameTransparency(nsIFrame* aFrame) {
   if (HasNonZeroCorner(aFrame->GetStyleContext()->GetStyleBorder()->mBorderRadius))
     return eTransparencyTransparent;
 
-  if (aFrame->IsThemed())
-    return eTransparencyOpaque;
+  nsTransparencyMode transparency;
+  if (aFrame->IsThemed(&transparency))
+    return transparency;
 
   if (aFrame->GetStyleDisplay()->mAppearance == NS_THEME_WIN_GLASS)
     return eTransparencyGlass;
diff --git a/layout/generic/nsIFrame.h b/layout/generic/nsIFrame.h
index dd8335fe9234..d9f2b5398d48 100644
--- a/layout/generic/nsIFrame.h
+++ b/layout/generic/nsIFrame.h
@@ -842,15 +842,20 @@ public:
                         const nsRect&               aDirtyRect,
                         const nsDisplayListSet&     aLists);
 
-  PRBool IsThemed() {
-    return IsThemed(GetStyleDisplay());
+  PRBool IsThemed(nsTransparencyMode* aTransparencyMode = nsnull) {
+    return IsThemed(GetStyleDisplay(), aTransparencyMode);
   }
-  PRBool IsThemed(const nsStyleDisplay* aDisp) {
+  PRBool IsThemed(const nsStyleDisplay* aDisp,
+                  nsTransparencyMode* aTransparencyMode = nsnull) {
     if (!aDisp->mAppearance)
       return PR_FALSE;
     nsPresContext* pc = PresContext();
     nsITheme *theme = pc->GetTheme();
-    return theme && theme->ThemeSupportsWidget(pc, this, aDisp->mAppearance);
+    if(!theme || !theme->ThemeSupportsWidget(pc, this, aDisp->mAppearance))
+      return PR_FALSE;
+    if (aTransparencyMode)
+      *aTransparencyMode = theme->GetWidgetTransparency(aDisp->mAppearance);
+    return PR_TRUE;
   }
   
   /**
diff --git a/widget/public/nsIWidget.h b/widget/public/nsIWidget.h
index ea61dc8bd777..24640007b9cc 100644
--- a/widget/public/nsIWidget.h
+++ b/widget/public/nsIWidget.h
@@ -46,6 +46,7 @@
 #include "prthread.h"
 #include "nsEvent.h"
 #include "nsCOMPtr.h"
+#include "nsITheme.h"
 
 // forward declarations
 class   nsIAppShell;
@@ -237,12 +238,6 @@ enum nsTopLevelWidgetZPlacement { // for PlaceBehind()
   eZPlacementTop          // top of the window stack
 };
 
-enum nsTransparencyMode {
-  eTransparencyOpaque = 0,  // Fully opaque
-  eTransparencyTransparent, // Parts of the window may be transparent
-  eTransparencyGlass        // Transparent parts of the window have Vista AeroGlass effect applied
-};
-
 /**
  * Basic struct for widget initialization data.
  * @see Create member function of nsIWidget
diff --git a/widget/src/cocoa/nsChildView.mm b/widget/src/cocoa/nsChildView.mm
index eaf4e4f6f543..b30bec48f0e1 100644
--- a/widget/src/cocoa/nsChildView.mm
+++ b/widget/src/cocoa/nsChildView.mm
@@ -2933,7 +2933,7 @@ NSEvent* gLastDragEvent = nil;
 static const PRInt32 sShadowInvalidationInterval = 100;
 - (void)maybeInvalidateShadow
 {
-  if (!mIsTransparent || ![mWindow hasShadow])
+  if ([mWindow isOpaque] || ![mWindow hasShadow])
     return;
 
   PRIntervalTime now = PR_IntervalNow();
diff --git a/widget/src/cocoa/nsNativeThemeCocoa.h b/widget/src/cocoa/nsNativeThemeCocoa.h
index fb18cdf9bf23..10ef79f8ef0d 100644
--- a/widget/src/cocoa/nsNativeThemeCocoa.h
+++ b/widget/src/cocoa/nsNativeThemeCocoa.h
@@ -88,6 +88,7 @@ public:
   PRBool WidgetIsContainer(PRUint8 aWidgetType);
   PRBool ThemeDrawsFocusForWidget(nsPresContext* aPresContext, nsIFrame* aFrame, PRUint8 aWidgetType);
   PRBool ThemeNeedsComboboxDropmarker();
+  virtual nsTransparencyMode GetWidgetTransparency(PRUint8 aWidgetType);
 
 protected:  
 
diff --git a/widget/src/cocoa/nsNativeThemeCocoa.mm b/widget/src/cocoa/nsNativeThemeCocoa.mm
index 9e70dabdc82d..a51d5b955b49 100644
--- a/widget/src/cocoa/nsNativeThemeCocoa.mm
+++ b/widget/src/cocoa/nsNativeThemeCocoa.mm
@@ -1439,8 +1439,10 @@ nsNativeThemeCocoa::DrawWidgetBackground(nsIRenderingContext* aContext, nsIFrame
         version: 0,
         menuType: IsDisabled(aFrame) ? kThemeMenuTypeInactive : kThemeMenuTypePopUp
       };
-
-      HIThemeDrawMenuBackground(&macRect, &mdi, cgContext, HITHEME_ORIENTATION);
+      // The rounded corners draw outside the frame.
+      CGRect deflatedRect = CGRectMake(macRect.origin.x, macRect.origin.y + 4,
+                                       macRect.size.width, macRect.size.height - 8);
+      HIThemeDrawMenuBackground(&deflatedRect, &mdi, cgContext, HITHEME_ORIENTATION);
     }
       break;
 
@@ -2288,3 +2290,12 @@ nsNativeThemeCocoa::ThemeNeedsComboboxDropmarker()
 {
   return PR_FALSE;
 }
+
+nsTransparencyMode
+nsNativeThemeCocoa::GetWidgetTransparency(PRUint8 aWidgetType)
+{
+  if (aWidgetType == NS_THEME_MENUPOPUP)
+    return eTransparencyTransparent;
+
+  return eTransparencyOpaque;
+}
diff --git a/widget/src/gtk2/nsNativeThemeGTK.cpp b/widget/src/gtk2/nsNativeThemeGTK.cpp
index c335d4854c65..b837bb9742c9 100644
--- a/widget/src/gtk2/nsNativeThemeGTK.cpp
+++ b/widget/src/gtk2/nsNativeThemeGTK.cpp
@@ -1314,3 +1314,9 @@ nsNativeThemeGTK::ThemeNeedsComboboxDropmarker()
 {
   return PR_FALSE;
 }
+
+nsTransparencyMode
+nsNativeThemeGTK::GetWidgetTransparency(PRUint8 aWidgetType)
+{
+  return eTransparencyOpaque;
+}
diff --git a/widget/src/gtk2/nsNativeThemeGTK.h b/widget/src/gtk2/nsNativeThemeGTK.h
index 291b0bc651da..eb3658d30668 100644
--- a/widget/src/gtk2/nsNativeThemeGTK.h
+++ b/widget/src/gtk2/nsNativeThemeGTK.h
@@ -92,6 +92,8 @@ public:
 
   PRBool ThemeNeedsComboboxDropmarker();
 
+  virtual nsTransparencyMode GetWidgetTransparency(PRUint8 aWidgetType);
+
   nsNativeThemeGTK();
   virtual ~nsNativeThemeGTK();
 
diff --git a/widget/src/qt/nsNativeThemeQt.cpp b/widget/src/qt/nsNativeThemeQt.cpp
index d0d8624e7078..ca35aa4081bc 100644
--- a/widget/src/qt/nsNativeThemeQt.cpp
+++ b/widget/src/qt/nsNativeThemeQt.cpp
@@ -563,6 +563,12 @@ nsNativeThemeQt::ThemeNeedsComboboxDropmarker()
     return PR_TRUE;
 }
 
+nsTransparencyMode
+nsNativeThemeQt::GetWidgetTransparency(PRUint8 aWidgetType)
+{
+  return eTransparencyOpaque;
+}
+
 void
 nsNativeThemeQt::InitButtonStyle(PRUint8 aWidgetType,
                                  nsIFrame* aFrame,
diff --git a/widget/src/qt/nsNativeThemeQt.h b/widget/src/qt/nsNativeThemeQt.h
index 49cfe96957ce..a513184f281c 100644
--- a/widget/src/qt/nsNativeThemeQt.h
+++ b/widget/src/qt/nsNativeThemeQt.h
@@ -99,6 +99,8 @@ public:
 
   PRBool ThemeNeedsComboboxDropmarker();
 
+  virtual nsTransparencyMode GetWidgetTransparency(PRUint8 aWidgetType);
+
   nsNativeThemeQt();
   virtual ~nsNativeThemeQt();
 
diff --git a/widget/src/windows/nsNativeThemeWin.cpp b/widget/src/windows/nsNativeThemeWin.cpp
index 3a8e41f3acbe..91c518c6403a 100644
--- a/widget/src/windows/nsNativeThemeWin.cpp
+++ b/widget/src/windows/nsNativeThemeWin.cpp
@@ -1650,6 +1650,12 @@ nsNativeThemeWin::ThemeNeedsComboboxDropmarker()
   return PR_TRUE;
 }
 
+nsTransparencyMode
+nsNativeThemeWin::GetWidgetTransparency(PRUint8 aWidgetType)
+{
+  return eTransparencyOpaque;
+}
+
 /* Windows 9x/NT/2000/Classic XP Theme Support */
 
 PRBool 
diff --git a/widget/src/windows/nsNativeThemeWin.h b/widget/src/windows/nsNativeThemeWin.h
index b0e7993af3ba..b02e9ad93129 100644
--- a/widget/src/windows/nsNativeThemeWin.h
+++ b/widget/src/windows/nsNativeThemeWin.h
@@ -75,6 +75,8 @@ public:
                                   nsSize* aResult,
                                   PRBool* aIsOverridable);
 
+  virtual nsTransparencyMode GetWidgetTransparency(PRUint8 aWidgetType);
+
   NS_IMETHOD WidgetStateChanged(nsIFrame* aFrame, PRUint8 aWidgetType, 
                                 nsIAtom* aAttribute, PRBool* aShouldRepaint);