diff --git a/layout/forms/nsFieldSetFrame.cpp b/layout/forms/nsFieldSetFrame.cpp
index dba2e8ba2d8..41a6e6b9328 100644
--- a/layout/forms/nsFieldSetFrame.cpp
+++ b/layout/forms/nsFieldSetFrame.cpp
@@ -342,6 +342,9 @@ nsFieldSetFrame::Reflow(nsIPresContext& aPresContext,
   nscoord contentWidth = contentSize.width + borderPadding.left + borderPadding.right;
 
   aDesiredSize.width = (legendWidth > contentWidth) ? legendWidth : contentWidth;
+  if (aReflowState.HaveConstrainedWidth() && (aReflowState.minWidth > aDesiredSize.width)) {
+    aDesiredSize.width = aReflowState.minWidth;
+  }
 
   // Place the legend 
   nsRect legendRect(0, 0, 0, 0);
@@ -402,6 +405,9 @@ nsFieldSetFrame::Reflow(nsIPresContext& aPresContext,
   aDesiredSize.height  = contentTopOffset + contentSize.height + borderPadding.bottom;
   if (mInline) // XXX parents don't yet ...... 
     aDesiredSize.height += margin.bottom;
+  if (aReflowState.HaveConstrainedHeight() && (aReflowState.minHeight > aDesiredSize.height)) {
+    aDesiredSize.height = aReflowState.minHeight;
+  }
   aDesiredSize.ascent  = aDesiredSize.height;
   aDesiredSize.descent = 0;
   if (nsnull != aDesiredSize.maxElementSize) {
diff --git a/layout/forms/nsHTMLButtonControlFrame.cpp b/layout/forms/nsHTMLButtonControlFrame.cpp
index 9ffca74d8a3..a1e20471de6 100644
--- a/layout/forms/nsHTMLButtonControlFrame.cpp
+++ b/layout/forms/nsHTMLButtonControlFrame.cpp
@@ -605,6 +605,15 @@ nsHTMLButtonControlFrame::Reflow(nsIPresContext& aPresContext,
     aDesiredSize.maxElementSize->width  += borderPadding.left + borderPadding.right;
     aDesiredSize.maxElementSize->height += borderPadding.top + borderPadding.bottom;
   }
+
+  // if we are constrained and the child is smaller, use the constrained values
+  if (aReflowState.HaveConstrainedWidth() && (aDesiredSize.width < aReflowState.minWidth)) {
+    aDesiredSize.width = aReflowState.minWidth;
+  }
+  if (aReflowState.HaveConstrainedHeight() && (aDesiredSize.height < aReflowState.minHeight)) {
+    aDesiredSize.height = aReflowState.minHeight;
+  }
+
   aDesiredSize.ascent  = aDesiredSize.height;
   aDesiredSize.descent = 0;
 
diff --git a/layout/forms/nsLegendFrame.cpp b/layout/forms/nsLegendFrame.cpp
index bdc44428659..9606a51dcda 100644
--- a/layout/forms/nsLegendFrame.cpp
+++ b/layout/forms/nsLegendFrame.cpp
@@ -146,7 +146,14 @@ nsLegendFrame::Reflow(nsIPresContext& aPresContext,
 
   // add in our border and padding to the size of the child
   aDesiredSize.width  += borderPadding.left + borderPadding.right;
+  if (aReflowState.HaveConstrainedWidth() && (aReflowState.minWidth > aDesiredSize.width)) {
+    aDesiredSize.width = aReflowState.minWidth;
+  }
+
   aDesiredSize.height += borderPadding.top + borderPadding.bottom;
+  if (aReflowState.HaveConstrainedHeight() && (aReflowState.minHeight > aDesiredSize.height)) {
+    aDesiredSize.height = aReflowState.minHeight;
+  }
 
   // adjust our max element size, if necessary
   if (aDesiredSize.maxElementSize) {
diff --git a/layout/html/forms/src/nsFieldSetFrame.cpp b/layout/html/forms/src/nsFieldSetFrame.cpp
index dba2e8ba2d8..41a6e6b9328 100644
--- a/layout/html/forms/src/nsFieldSetFrame.cpp
+++ b/layout/html/forms/src/nsFieldSetFrame.cpp
@@ -342,6 +342,9 @@ nsFieldSetFrame::Reflow(nsIPresContext& aPresContext,
   nscoord contentWidth = contentSize.width + borderPadding.left + borderPadding.right;
 
   aDesiredSize.width = (legendWidth > contentWidth) ? legendWidth : contentWidth;
+  if (aReflowState.HaveConstrainedWidth() && (aReflowState.minWidth > aDesiredSize.width)) {
+    aDesiredSize.width = aReflowState.minWidth;
+  }
 
   // Place the legend 
   nsRect legendRect(0, 0, 0, 0);
@@ -402,6 +405,9 @@ nsFieldSetFrame::Reflow(nsIPresContext& aPresContext,
   aDesiredSize.height  = contentTopOffset + contentSize.height + borderPadding.bottom;
   if (mInline) // XXX parents don't yet ...... 
     aDesiredSize.height += margin.bottom;
+  if (aReflowState.HaveConstrainedHeight() && (aReflowState.minHeight > aDesiredSize.height)) {
+    aDesiredSize.height = aReflowState.minHeight;
+  }
   aDesiredSize.ascent  = aDesiredSize.height;
   aDesiredSize.descent = 0;
   if (nsnull != aDesiredSize.maxElementSize) {
diff --git a/layout/html/forms/src/nsHTMLButtonControlFrame.cpp b/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
index 9ffca74d8a3..a1e20471de6 100644
--- a/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
+++ b/layout/html/forms/src/nsHTMLButtonControlFrame.cpp
@@ -605,6 +605,15 @@ nsHTMLButtonControlFrame::Reflow(nsIPresContext& aPresContext,
     aDesiredSize.maxElementSize->width  += borderPadding.left + borderPadding.right;
     aDesiredSize.maxElementSize->height += borderPadding.top + borderPadding.bottom;
   }
+
+  // if we are constrained and the child is smaller, use the constrained values
+  if (aReflowState.HaveConstrainedWidth() && (aDesiredSize.width < aReflowState.minWidth)) {
+    aDesiredSize.width = aReflowState.minWidth;
+  }
+  if (aReflowState.HaveConstrainedHeight() && (aDesiredSize.height < aReflowState.minHeight)) {
+    aDesiredSize.height = aReflowState.minHeight;
+  }
+
   aDesiredSize.ascent  = aDesiredSize.height;
   aDesiredSize.descent = 0;
 
diff --git a/layout/html/forms/src/nsLegendFrame.cpp b/layout/html/forms/src/nsLegendFrame.cpp
index bdc44428659..9606a51dcda 100644
--- a/layout/html/forms/src/nsLegendFrame.cpp
+++ b/layout/html/forms/src/nsLegendFrame.cpp
@@ -146,7 +146,14 @@ nsLegendFrame::Reflow(nsIPresContext& aPresContext,
 
   // add in our border and padding to the size of the child
   aDesiredSize.width  += borderPadding.left + borderPadding.right;
+  if (aReflowState.HaveConstrainedWidth() && (aReflowState.minWidth > aDesiredSize.width)) {
+    aDesiredSize.width = aReflowState.minWidth;
+  }
+
   aDesiredSize.height += borderPadding.top + borderPadding.bottom;
+  if (aReflowState.HaveConstrainedHeight() && (aReflowState.minHeight > aDesiredSize.height)) {
+    aDesiredSize.height = aReflowState.minHeight;
+  }
 
   // adjust our max element size, if necessary
   if (aDesiredSize.maxElementSize) {