diff --git a/content/base/src/nsRuleNode.cpp b/content/base/src/nsRuleNode.cpp
index 659eb84a446b..249b8dd0c23b 100644
--- a/content/base/src/nsRuleNode.cpp
+++ b/content/base/src/nsRuleNode.cpp
@@ -3124,12 +3124,14 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     parentBG = NS_STATIC_CAST(const nsStyleBackground*,
                          parentContext->GetStyleData(eStyleStruct_Background));
   PRBool inherited = aInherited;
+  // save parentFlags in case bg == parentBG and we clobber them later
+  PRUint8 parentFlags = parentBG->mBackgroundFlags;
 
   // background-color: color, string, enum (flags), inherit
   if (eCSSUnit_Inherit == colorData.mBackColor.GetUnit()) { // do inherit first, so SetColor doesn't do it
     bg->mBackgroundColor = parentBG->mBackgroundColor;
     bg->mBackgroundFlags &= ~NS_STYLE_BG_COLOR_TRANSPARENT;
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & NS_STYLE_BG_COLOR_TRANSPARENT);
+    bg->mBackgroundFlags |= (parentFlags & NS_STYLE_BG_COLOR_TRANSPARENT);
     inherited = PR_TRUE;
   }
   else if (SetColor(colorData.mBackColor, parentBG->mBackgroundColor, 
@@ -3154,7 +3156,7 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     inherited = PR_TRUE;
     bg->mBackgroundImage = parentBG->mBackgroundImage;
     bg->mBackgroundFlags &= ~NS_STYLE_BG_IMAGE_NONE;
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & NS_STYLE_BG_IMAGE_NONE);
+    bg->mBackgroundFlags |= (parentFlags & NS_STYLE_BG_IMAGE_NONE);
   }
 
   // background-repeat: enum, inherit
@@ -3196,7 +3198,7 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     inherited = PR_TRUE;
     bg->mBackgroundXPosition = parentBG->mBackgroundXPosition;
     bg->mBackgroundFlags &= ~(NS_STYLE_BG_X_POSITION_LENGTH | NS_STYLE_BG_X_POSITION_PERCENT);
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & (NS_STYLE_BG_X_POSITION_LENGTH | NS_STYLE_BG_X_POSITION_PERCENT));
+    bg->mBackgroundFlags |= (parentFlags & (NS_STYLE_BG_X_POSITION_LENGTH | NS_STYLE_BG_X_POSITION_PERCENT));
   }
 
   if (eCSSUnit_Percent == colorData.mBackPositionY.GetUnit()) {
@@ -3219,7 +3221,7 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     inherited = PR_TRUE;
     bg->mBackgroundYPosition = parentBG->mBackgroundYPosition;
     bg->mBackgroundFlags &= ~(NS_STYLE_BG_Y_POSITION_LENGTH | NS_STYLE_BG_Y_POSITION_PERCENT);
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & (NS_STYLE_BG_Y_POSITION_LENGTH | NS_STYLE_BG_Y_POSITION_PERCENT));
+    bg->mBackgroundFlags |= (parentFlags & (NS_STYLE_BG_Y_POSITION_LENGTH | NS_STYLE_BG_Y_POSITION_PERCENT));
   }
 
   if (inherited)
diff --git a/layout/generic/nsFrameFrame.cpp b/layout/generic/nsFrameFrame.cpp
index d7294b5fa557..912f2be78103 100644
--- a/layout/generic/nsFrameFrame.cpp
+++ b/layout/generic/nsFrameFrame.cpp
@@ -220,6 +220,10 @@ public:
                    nsFramePaintLayer    aWhichLayer,
                    PRUint32             aFlags);
 
+  // Make sure we never think this frame is opaque because it has
+  // a background set; we won't be painting it in most cases
+  virtual PRBool CanPaintBackground() { return PR_FALSE; }
+
   /**
     * @see nsIFrame::Reflow
     */
@@ -460,17 +464,8 @@ nsHTMLFrameOuterFrame::Paint(nsIPresContext*      aPresContext,
   }
 
   //printf("outer paint %X (%d,%d,%d,%d) \n", this, aDirtyRect.x, aDirtyRect.y, aDirtyRect.width, aDirtyRect.height);
-  nsIFrame* firstChild = mFrames.FirstChild();
-  if (nsnull != firstChild) {
-    firstChild->Paint(aPresContext, aRenderingContext, aDirtyRect,
-                      aWhichLayer);
-  }
-  if (IsInline()) {
-    return nsHTMLContainerFrame::Paint(aPresContext, aRenderingContext,
-                                       aDirtyRect, aWhichLayer);
-  } else {
-    return NS_OK;
-  }
+  return nsHTMLContainerFrame::Paint(aPresContext, aRenderingContext,
+                                     aDirtyRect, aWhichLayer);
 }
 
 #ifdef DEBUG
diff --git a/layout/html/document/src/html.css b/layout/html/document/src/html.css
index c24447039039..5bb870678b6d 100644
--- a/layout/html/document/src/html.css
+++ b/layout/html/document/src/html.css
@@ -440,12 +440,10 @@ frameset {
 }
 
 frame {
-  background-color: transparent ! important; /* (b=49779) */
   -moz-user-focus: normal;
 }
 
 iframe {
-  background-color: transparent ! important; /* (b=49779) */
   border: 2px inset;
   -moz-user-focus: normal;
 }
diff --git a/layout/html/document/src/nsFrameFrame.cpp b/layout/html/document/src/nsFrameFrame.cpp
index d7294b5fa557..912f2be78103 100644
--- a/layout/html/document/src/nsFrameFrame.cpp
+++ b/layout/html/document/src/nsFrameFrame.cpp
@@ -220,6 +220,10 @@ public:
                    nsFramePaintLayer    aWhichLayer,
                    PRUint32             aFlags);
 
+  // Make sure we never think this frame is opaque because it has
+  // a background set; we won't be painting it in most cases
+  virtual PRBool CanPaintBackground() { return PR_FALSE; }
+
   /**
     * @see nsIFrame::Reflow
     */
@@ -460,17 +464,8 @@ nsHTMLFrameOuterFrame::Paint(nsIPresContext*      aPresContext,
   }
 
   //printf("outer paint %X (%d,%d,%d,%d) \n", this, aDirtyRect.x, aDirtyRect.y, aDirtyRect.width, aDirtyRect.height);
-  nsIFrame* firstChild = mFrames.FirstChild();
-  if (nsnull != firstChild) {
-    firstChild->Paint(aPresContext, aRenderingContext, aDirtyRect,
-                      aWhichLayer);
-  }
-  if (IsInline()) {
-    return nsHTMLContainerFrame::Paint(aPresContext, aRenderingContext,
-                                       aDirtyRect, aWhichLayer);
-  } else {
-    return NS_OK;
-  }
+  return nsHTMLContainerFrame::Paint(aPresContext, aRenderingContext,
+                                     aDirtyRect, aWhichLayer);
 }
 
 #ifdef DEBUG
diff --git a/layout/style/html.css b/layout/style/html.css
index c24447039039..5bb870678b6d 100644
--- a/layout/style/html.css
+++ b/layout/style/html.css
@@ -440,12 +440,10 @@ frameset {
 }
 
 frame {
-  background-color: transparent ! important; /* (b=49779) */
   -moz-user-focus: normal;
 }
 
 iframe {
-  background-color: transparent ! important; /* (b=49779) */
   border: 2px inset;
   -moz-user-focus: normal;
 }
diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index 659eb84a446b..249b8dd0c23b 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -3124,12 +3124,14 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     parentBG = NS_STATIC_CAST(const nsStyleBackground*,
                          parentContext->GetStyleData(eStyleStruct_Background));
   PRBool inherited = aInherited;
+  // save parentFlags in case bg == parentBG and we clobber them later
+  PRUint8 parentFlags = parentBG->mBackgroundFlags;
 
   // background-color: color, string, enum (flags), inherit
   if (eCSSUnit_Inherit == colorData.mBackColor.GetUnit()) { // do inherit first, so SetColor doesn't do it
     bg->mBackgroundColor = parentBG->mBackgroundColor;
     bg->mBackgroundFlags &= ~NS_STYLE_BG_COLOR_TRANSPARENT;
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & NS_STYLE_BG_COLOR_TRANSPARENT);
+    bg->mBackgroundFlags |= (parentFlags & NS_STYLE_BG_COLOR_TRANSPARENT);
     inherited = PR_TRUE;
   }
   else if (SetColor(colorData.mBackColor, parentBG->mBackgroundColor, 
@@ -3154,7 +3156,7 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     inherited = PR_TRUE;
     bg->mBackgroundImage = parentBG->mBackgroundImage;
     bg->mBackgroundFlags &= ~NS_STYLE_BG_IMAGE_NONE;
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & NS_STYLE_BG_IMAGE_NONE);
+    bg->mBackgroundFlags |= (parentFlags & NS_STYLE_BG_IMAGE_NONE);
   }
 
   // background-repeat: enum, inherit
@@ -3196,7 +3198,7 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     inherited = PR_TRUE;
     bg->mBackgroundXPosition = parentBG->mBackgroundXPosition;
     bg->mBackgroundFlags &= ~(NS_STYLE_BG_X_POSITION_LENGTH | NS_STYLE_BG_X_POSITION_PERCENT);
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & (NS_STYLE_BG_X_POSITION_LENGTH | NS_STYLE_BG_X_POSITION_PERCENT));
+    bg->mBackgroundFlags |= (parentFlags & (NS_STYLE_BG_X_POSITION_LENGTH | NS_STYLE_BG_X_POSITION_PERCENT));
   }
 
   if (eCSSUnit_Percent == colorData.mBackPositionY.GetUnit()) {
@@ -3219,7 +3221,7 @@ nsRuleNode::ComputeBackgroundData(nsStyleStruct* aStartStruct, const nsCSSStruct
     inherited = PR_TRUE;
     bg->mBackgroundYPosition = parentBG->mBackgroundYPosition;
     bg->mBackgroundFlags &= ~(NS_STYLE_BG_Y_POSITION_LENGTH | NS_STYLE_BG_Y_POSITION_PERCENT);
-    bg->mBackgroundFlags |= (parentBG->mBackgroundFlags & (NS_STYLE_BG_Y_POSITION_LENGTH | NS_STYLE_BG_Y_POSITION_PERCENT));
+    bg->mBackgroundFlags |= (parentFlags & (NS_STYLE_BG_Y_POSITION_LENGTH | NS_STYLE_BG_Y_POSITION_PERCENT));
   }
 
   if (inherited)