diff --git a/content/html/content/src/nsGenericHTMLElement.cpp b/content/html/content/src/nsGenericHTMLElement.cpp
index a0ae178fbced..7246d3056678 100644
--- a/content/html/content/src/nsGenericHTMLElement.cpp
+++ b/content/html/content/src/nsGenericHTMLElement.cpp
@@ -2534,6 +2534,8 @@ static nsGenericHTMLElement::EnumTable kCompatTableHAlignTable[] = {
   { "char",   NS_STYLE_TEXT_ALIGN_CHAR },
   { "justify",NS_STYLE_TEXT_ALIGN_JUSTIFY },
   { "abscenter", NS_STYLE_TEXT_ALIGN_CENTER },
+  { "absmiddle", NS_STYLE_TEXT_ALIGN_CENTER },
+  { "middle", NS_STYLE_TEXT_ALIGN_CENTER },
   { 0 }
 };
 
diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 6c7a332ca9c9..b9754ccfea07 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -1502,12 +1502,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
 {
-  /*
-  ListTag(stdout);
-    printf(": begin reflow type %d availSize=%d,%d computedSize=%d,%d\n",
-           aReflowState.reason, aReflowState.availableWidth, aReflowState.availableHeight,
-           aReflowState.mComputedWidth, aReflowState.mComputedHeight);
-*/
   DO_GLOBAL_REFLOW_COUNT("nsBlockFrame", aReflowState.reason);
 
 #ifdef DEBUG
@@ -2570,14 +2564,24 @@ nsBlockFrame::PrepareResizeReflow(nsBlockReflowState& aState)
 
   nsLineBox* line = mLines;
   if (tryAndSkipLines) {
-    // The line's bounds are relative to the border edge of the frame
     nscoord newAvailWidth = aState.mReflowState.mComputedBorderPadding.left;
      
     if (NS_SHRINKWRAPWIDTH == aState.mReflowState.mComputedWidth) {
-      newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     } else {
-      newAvailWidth += aState.mReflowState.mComputedWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     }
+    NS_ASSERTION(NS_UNCONSTRAINEDSIZE != newAvailWidth, "bad math, newAvailWidth is infinite");
 
 #ifdef DEBUG
     if (gNoisyReflow) {
@@ -4450,13 +4454,14 @@ nsBlockFrame::ReflowInlineFrame(nsBlockReflowState& aState,
       if (NS_FAILED(rv)) {
         return rv;
       }
-
+#if 0
       // Mark next line dirty in case SplitLine didn't end up
       // pushing any frames.
       nsLineBox* next = aLine->mNext;
       if ((nsnull != next) && !next->IsBlock()) {
         next->MarkDirty();
       }
+#endif
     }
   }
   else if (NS_FRAME_IS_NOT_COMPLETE(frameReflowStatus)) {
diff --git a/layout/generic/nsBlockReflowState.cpp b/layout/generic/nsBlockReflowState.cpp
index 6c7a332ca9c9..b9754ccfea07 100644
--- a/layout/generic/nsBlockReflowState.cpp
+++ b/layout/generic/nsBlockReflowState.cpp
@@ -1502,12 +1502,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
 {
-  /*
-  ListTag(stdout);
-    printf(": begin reflow type %d availSize=%d,%d computedSize=%d,%d\n",
-           aReflowState.reason, aReflowState.availableWidth, aReflowState.availableHeight,
-           aReflowState.mComputedWidth, aReflowState.mComputedHeight);
-*/
   DO_GLOBAL_REFLOW_COUNT("nsBlockFrame", aReflowState.reason);
 
 #ifdef DEBUG
@@ -2570,14 +2564,24 @@ nsBlockFrame::PrepareResizeReflow(nsBlockReflowState& aState)
 
   nsLineBox* line = mLines;
   if (tryAndSkipLines) {
-    // The line's bounds are relative to the border edge of the frame
     nscoord newAvailWidth = aState.mReflowState.mComputedBorderPadding.left;
      
     if (NS_SHRINKWRAPWIDTH == aState.mReflowState.mComputedWidth) {
-      newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     } else {
-      newAvailWidth += aState.mReflowState.mComputedWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     }
+    NS_ASSERTION(NS_UNCONSTRAINEDSIZE != newAvailWidth, "bad math, newAvailWidth is infinite");
 
 #ifdef DEBUG
     if (gNoisyReflow) {
@@ -4450,13 +4454,14 @@ nsBlockFrame::ReflowInlineFrame(nsBlockReflowState& aState,
       if (NS_FAILED(rv)) {
         return rv;
       }
-
+#if 0
       // Mark next line dirty in case SplitLine didn't end up
       // pushing any frames.
       nsLineBox* next = aLine->mNext;
       if ((nsnull != next) && !next->IsBlock()) {
         next->MarkDirty();
       }
+#endif
     }
   }
   else if (NS_FRAME_IS_NOT_COMPLETE(frameReflowStatus)) {
diff --git a/layout/generic/nsBlockReflowState.h b/layout/generic/nsBlockReflowState.h
index 6c7a332ca9c9..b9754ccfea07 100644
--- a/layout/generic/nsBlockReflowState.h
+++ b/layout/generic/nsBlockReflowState.h
@@ -1502,12 +1502,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
 {
-  /*
-  ListTag(stdout);
-    printf(": begin reflow type %d availSize=%d,%d computedSize=%d,%d\n",
-           aReflowState.reason, aReflowState.availableWidth, aReflowState.availableHeight,
-           aReflowState.mComputedWidth, aReflowState.mComputedHeight);
-*/
   DO_GLOBAL_REFLOW_COUNT("nsBlockFrame", aReflowState.reason);
 
 #ifdef DEBUG
@@ -2570,14 +2564,24 @@ nsBlockFrame::PrepareResizeReflow(nsBlockReflowState& aState)
 
   nsLineBox* line = mLines;
   if (tryAndSkipLines) {
-    // The line's bounds are relative to the border edge of the frame
     nscoord newAvailWidth = aState.mReflowState.mComputedBorderPadding.left;
      
     if (NS_SHRINKWRAPWIDTH == aState.mReflowState.mComputedWidth) {
-      newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     } else {
-      newAvailWidth += aState.mReflowState.mComputedWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     }
+    NS_ASSERTION(NS_UNCONSTRAINEDSIZE != newAvailWidth, "bad math, newAvailWidth is infinite");
 
 #ifdef DEBUG
     if (gNoisyReflow) {
@@ -4450,13 +4454,14 @@ nsBlockFrame::ReflowInlineFrame(nsBlockReflowState& aState,
       if (NS_FAILED(rv)) {
         return rv;
       }
-
+#if 0
       // Mark next line dirty in case SplitLine didn't end up
       // pushing any frames.
       nsLineBox* next = aLine->mNext;
       if ((nsnull != next) && !next->IsBlock()) {
         next->MarkDirty();
       }
+#endif
     }
   }
   else if (NS_FRAME_IS_NOT_COMPLETE(frameReflowStatus)) {
diff --git a/layout/generic/nsHTMLReflowState.cpp b/layout/generic/nsHTMLReflowState.cpp
index d0b575b04b39..1b1b5fd711f9 100644
--- a/layout/generic/nsHTMLReflowState.cpp
+++ b/layout/generic/nsHTMLReflowState.cpp
@@ -1441,18 +1441,13 @@ nsHTMLReflowState::ComputeContainingBlockRectangle(nsIPresContext*          aPre
     if (NS_UNCONSTRAINEDSIZE == availableWidth) {
       aContainingBlockWidth = NS_UNCONSTRAINEDSIZE;
     }
-    // a table in quirks mode gets a containing block based on the viewport (less  
-    // body margins, border, padding) if the table is a child of the body.
+    // an element in quirks mode gets a containing block based on the viewport (less  
+    // body margins, border, padding) if the element is a child of the body.
     if (NS_AUTOHEIGHT == aContainingBlockHeight) {
-      nsCOMPtr<nsIAtom> fType;
-      frame->GetFrameType(getter_AddRefs(fType));
-      if (nsLayoutAtoms::tableFrame == fType.get() ||
-          nsLayoutAtoms::htmlFrameOuterFrame == fType.get()) {
-        nsCompatibility mode;
-        aPresContext->GetCompatibilityMode(&mode);
-        if (eCompatibility_NavQuirks == mode) {
-          aContainingBlockHeight = CalcQuirkContainingBlockHeight(*aContainingBlockRS);
-        }
+      nsCompatibility mode;
+      aPresContext->GetCompatibilityMode(&mode);
+      if (eCompatibility_NavQuirks == mode) {
+        aContainingBlockHeight = CalcQuirkContainingBlockHeight(*aContainingBlockRS);
       }
     }
   }
@@ -1551,8 +1546,34 @@ nsHTMLReflowState::InitConstraints(nsIPresContext* aPresContext,
     // that depends on the content height
     if (eStyleUnit_Percent == heightUnit) {
       if (NS_AUTOHEIGHT == aContainingBlockHeight) {
-        // Interpret the height like 'auto'
-        heightUnit = eStyleUnit_Auto;
+        // this if clause enables %-height on replaced inline frames,
+        // such as images.  See bug 54119.  The else clause "heightUnit = eStyleUnit_Auto;"
+        // used to be called exclusively.
+        if (NS_FRAME_REPLACED(NS_CSS_FRAME_TYPE_INLINE) == mFrameType) {
+          // Get the containing block reflow state
+          const nsHTMLReflowState* cbrs =
+            GetContainingBlockReflowState(parentReflowState);
+          NS_ASSERTION(nsnull != cbrs, "no containing block");
+          nsCompatibility mode;
+          aPresContext->GetCompatibilityMode(&mode);
+          // in quirks mode, get the cb height using the special quirk method
+          if (eCompatibility_NavQuirks == mode) {
+            aContainingBlockHeight = CalcQuirkContainingBlockHeight(*cbrs);
+          }
+          // in standard mode, use the cb height.  if it's "auto", as will be the case
+          // by default in BODY, use auto height as per CSS2 spec.
+          else 
+          {
+            if (NS_AUTOHEIGHT != cbrs->mComputedHeight)
+              aContainingBlockHeight = cbrs->mComputedHeight;
+            else
+              heightUnit = eStyleUnit_Auto;
+          }
+        }
+        else {
+          // default to interpreting the height like 'auto'
+          heightUnit = eStyleUnit_Auto;
+        }
       }
     }
 
@@ -1849,6 +1870,7 @@ nsHTMLReflowState::ComputeBlockBoxData(nsIPresContext* aPresContext,
           // Use 'min-width' as the value for 'width'
           mComputedWidth = mComputedMinWidth;
         }
+
       }
     }
   } else {
diff --git a/layout/html/base/src/nsBlockFrame.cpp b/layout/html/base/src/nsBlockFrame.cpp
index 6c7a332ca9c9..b9754ccfea07 100644
--- a/layout/html/base/src/nsBlockFrame.cpp
+++ b/layout/html/base/src/nsBlockFrame.cpp
@@ -1502,12 +1502,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
 {
-  /*
-  ListTag(stdout);
-    printf(": begin reflow type %d availSize=%d,%d computedSize=%d,%d\n",
-           aReflowState.reason, aReflowState.availableWidth, aReflowState.availableHeight,
-           aReflowState.mComputedWidth, aReflowState.mComputedHeight);
-*/
   DO_GLOBAL_REFLOW_COUNT("nsBlockFrame", aReflowState.reason);
 
 #ifdef DEBUG
@@ -2570,14 +2564,24 @@ nsBlockFrame::PrepareResizeReflow(nsBlockReflowState& aState)
 
   nsLineBox* line = mLines;
   if (tryAndSkipLines) {
-    // The line's bounds are relative to the border edge of the frame
     nscoord newAvailWidth = aState.mReflowState.mComputedBorderPadding.left;
      
     if (NS_SHRINKWRAPWIDTH == aState.mReflowState.mComputedWidth) {
-      newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     } else {
-      newAvailWidth += aState.mReflowState.mComputedWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     }
+    NS_ASSERTION(NS_UNCONSTRAINEDSIZE != newAvailWidth, "bad math, newAvailWidth is infinite");
 
 #ifdef DEBUG
     if (gNoisyReflow) {
@@ -4450,13 +4454,14 @@ nsBlockFrame::ReflowInlineFrame(nsBlockReflowState& aState,
       if (NS_FAILED(rv)) {
         return rv;
       }
-
+#if 0
       // Mark next line dirty in case SplitLine didn't end up
       // pushing any frames.
       nsLineBox* next = aLine->mNext;
       if ((nsnull != next) && !next->IsBlock()) {
         next->MarkDirty();
       }
+#endif
     }
   }
   else if (NS_FRAME_IS_NOT_COMPLETE(frameReflowStatus)) {
diff --git a/layout/html/base/src/nsBlockReflowState.cpp b/layout/html/base/src/nsBlockReflowState.cpp
index 6c7a332ca9c9..b9754ccfea07 100644
--- a/layout/html/base/src/nsBlockReflowState.cpp
+++ b/layout/html/base/src/nsBlockReflowState.cpp
@@ -1502,12 +1502,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
 {
-  /*
-  ListTag(stdout);
-    printf(": begin reflow type %d availSize=%d,%d computedSize=%d,%d\n",
-           aReflowState.reason, aReflowState.availableWidth, aReflowState.availableHeight,
-           aReflowState.mComputedWidth, aReflowState.mComputedHeight);
-*/
   DO_GLOBAL_REFLOW_COUNT("nsBlockFrame", aReflowState.reason);
 
 #ifdef DEBUG
@@ -2570,14 +2564,24 @@ nsBlockFrame::PrepareResizeReflow(nsBlockReflowState& aState)
 
   nsLineBox* line = mLines;
   if (tryAndSkipLines) {
-    // The line's bounds are relative to the border edge of the frame
     nscoord newAvailWidth = aState.mReflowState.mComputedBorderPadding.left;
      
     if (NS_SHRINKWRAPWIDTH == aState.mReflowState.mComputedWidth) {
-      newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     } else {
-      newAvailWidth += aState.mReflowState.mComputedWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     }
+    NS_ASSERTION(NS_UNCONSTRAINEDSIZE != newAvailWidth, "bad math, newAvailWidth is infinite");
 
 #ifdef DEBUG
     if (gNoisyReflow) {
@@ -4450,13 +4454,14 @@ nsBlockFrame::ReflowInlineFrame(nsBlockReflowState& aState,
       if (NS_FAILED(rv)) {
         return rv;
       }
-
+#if 0
       // Mark next line dirty in case SplitLine didn't end up
       // pushing any frames.
       nsLineBox* next = aLine->mNext;
       if ((nsnull != next) && !next->IsBlock()) {
         next->MarkDirty();
       }
+#endif
     }
   }
   else if (NS_FRAME_IS_NOT_COMPLETE(frameReflowStatus)) {
diff --git a/layout/html/base/src/nsBlockReflowState.h b/layout/html/base/src/nsBlockReflowState.h
index 6c7a332ca9c9..b9754ccfea07 100644
--- a/layout/html/base/src/nsBlockReflowState.h
+++ b/layout/html/base/src/nsBlockReflowState.h
@@ -1502,12 +1502,6 @@ nsBlockFrame::Reflow(nsIPresContext*          aPresContext,
                      const nsHTMLReflowState& aReflowState,
                      nsReflowStatus&          aStatus)
 {
-  /*
-  ListTag(stdout);
-    printf(": begin reflow type %d availSize=%d,%d computedSize=%d,%d\n",
-           aReflowState.reason, aReflowState.availableWidth, aReflowState.availableHeight,
-           aReflowState.mComputedWidth, aReflowState.mComputedHeight);
-*/
   DO_GLOBAL_REFLOW_COUNT("nsBlockFrame", aReflowState.reason);
 
 #ifdef DEBUG
@@ -2570,14 +2564,24 @@ nsBlockFrame::PrepareResizeReflow(nsBlockReflowState& aState)
 
   nsLineBox* line = mLines;
   if (tryAndSkipLines) {
-    // The line's bounds are relative to the border edge of the frame
     nscoord newAvailWidth = aState.mReflowState.mComputedBorderPadding.left;
      
     if (NS_SHRINKWRAPWIDTH == aState.mReflowState.mComputedWidth) {
-      newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedMaxWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     } else {
-      newAvailWidth += aState.mReflowState.mComputedWidth;
+      if (NS_UNCONSTRAINEDSIZE != aState.mReflowState.mComputedMaxWidth) {
+        newAvailWidth += aState.mReflowState.mComputedWidth;
+      }
+      else {
+        newAvailWidth += aState.mReflowState.availableWidth;
+      }
     }
+    NS_ASSERTION(NS_UNCONSTRAINEDSIZE != newAvailWidth, "bad math, newAvailWidth is infinite");
 
 #ifdef DEBUG
     if (gNoisyReflow) {
@@ -4450,13 +4454,14 @@ nsBlockFrame::ReflowInlineFrame(nsBlockReflowState& aState,
       if (NS_FAILED(rv)) {
         return rv;
       }
-
+#if 0
       // Mark next line dirty in case SplitLine didn't end up
       // pushing any frames.
       nsLineBox* next = aLine->mNext;
       if ((nsnull != next) && !next->IsBlock()) {
         next->MarkDirty();
       }
+#endif
     }
   }
   else if (NS_FRAME_IS_NOT_COMPLETE(frameReflowStatus)) {
diff --git a/layout/html/base/src/nsHTMLReflowState.cpp b/layout/html/base/src/nsHTMLReflowState.cpp
index d0b575b04b39..1b1b5fd711f9 100644
--- a/layout/html/base/src/nsHTMLReflowState.cpp
+++ b/layout/html/base/src/nsHTMLReflowState.cpp
@@ -1441,18 +1441,13 @@ nsHTMLReflowState::ComputeContainingBlockRectangle(nsIPresContext*          aPre
     if (NS_UNCONSTRAINEDSIZE == availableWidth) {
       aContainingBlockWidth = NS_UNCONSTRAINEDSIZE;
     }
-    // a table in quirks mode gets a containing block based on the viewport (less  
-    // body margins, border, padding) if the table is a child of the body.
+    // an element in quirks mode gets a containing block based on the viewport (less  
+    // body margins, border, padding) if the element is a child of the body.
     if (NS_AUTOHEIGHT == aContainingBlockHeight) {
-      nsCOMPtr<nsIAtom> fType;
-      frame->GetFrameType(getter_AddRefs(fType));
-      if (nsLayoutAtoms::tableFrame == fType.get() ||
-          nsLayoutAtoms::htmlFrameOuterFrame == fType.get()) {
-        nsCompatibility mode;
-        aPresContext->GetCompatibilityMode(&mode);
-        if (eCompatibility_NavQuirks == mode) {
-          aContainingBlockHeight = CalcQuirkContainingBlockHeight(*aContainingBlockRS);
-        }
+      nsCompatibility mode;
+      aPresContext->GetCompatibilityMode(&mode);
+      if (eCompatibility_NavQuirks == mode) {
+        aContainingBlockHeight = CalcQuirkContainingBlockHeight(*aContainingBlockRS);
       }
     }
   }
@@ -1551,8 +1546,34 @@ nsHTMLReflowState::InitConstraints(nsIPresContext* aPresContext,
     // that depends on the content height
     if (eStyleUnit_Percent == heightUnit) {
       if (NS_AUTOHEIGHT == aContainingBlockHeight) {
-        // Interpret the height like 'auto'
-        heightUnit = eStyleUnit_Auto;
+        // this if clause enables %-height on replaced inline frames,
+        // such as images.  See bug 54119.  The else clause "heightUnit = eStyleUnit_Auto;"
+        // used to be called exclusively.
+        if (NS_FRAME_REPLACED(NS_CSS_FRAME_TYPE_INLINE) == mFrameType) {
+          // Get the containing block reflow state
+          const nsHTMLReflowState* cbrs =
+            GetContainingBlockReflowState(parentReflowState);
+          NS_ASSERTION(nsnull != cbrs, "no containing block");
+          nsCompatibility mode;
+          aPresContext->GetCompatibilityMode(&mode);
+          // in quirks mode, get the cb height using the special quirk method
+          if (eCompatibility_NavQuirks == mode) {
+            aContainingBlockHeight = CalcQuirkContainingBlockHeight(*cbrs);
+          }
+          // in standard mode, use the cb height.  if it's "auto", as will be the case
+          // by default in BODY, use auto height as per CSS2 spec.
+          else 
+          {
+            if (NS_AUTOHEIGHT != cbrs->mComputedHeight)
+              aContainingBlockHeight = cbrs->mComputedHeight;
+            else
+              heightUnit = eStyleUnit_Auto;
+          }
+        }
+        else {
+          // default to interpreting the height like 'auto'
+          heightUnit = eStyleUnit_Auto;
+        }
       }
     }
 
@@ -1849,6 +1870,7 @@ nsHTMLReflowState::ComputeBlockBoxData(nsIPresContext* aPresContext,
           // Use 'min-width' as the value for 'width'
           mComputedWidth = mComputedMinWidth;
         }
+
       }
     }
   } else {
diff --git a/layout/html/content/src/nsGenericHTMLElement.cpp b/layout/html/content/src/nsGenericHTMLElement.cpp
index a0ae178fbced..7246d3056678 100644
--- a/layout/html/content/src/nsGenericHTMLElement.cpp
+++ b/layout/html/content/src/nsGenericHTMLElement.cpp
@@ -2534,6 +2534,8 @@ static nsGenericHTMLElement::EnumTable kCompatTableHAlignTable[] = {
   { "char",   NS_STYLE_TEXT_ALIGN_CHAR },
   { "justify",NS_STYLE_TEXT_ALIGN_JUSTIFY },
   { "abscenter", NS_STYLE_TEXT_ALIGN_CENTER },
+  { "absmiddle", NS_STYLE_TEXT_ALIGN_CENTER },
+  { "middle", NS_STYLE_TEXT_ALIGN_CENTER },
   { 0 }
 };