From 9b5edcef2cf94d4375cf2b992e3db71c8b30f37d Mon Sep 17 00:00:00 2001
From: "reed@reedloden.com" <reed@reedloden.com>
Date: Wed, 7 Nov 2007 19:55:12 -0800
Subject: [PATCH] Bug 398144 - Make blocks that are margin-roots never consider
 themselves empty. [p=roc r+sr=dbaron a=blocking1.9+]

---
 layout/generic/nsBlockFrame.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/layout/generic/nsBlockFrame.cpp b/layout/generic/nsBlockFrame.cpp
index 4592defd7021..20c90e76f09e 100644
--- a/layout/generic/nsBlockFrame.cpp
+++ b/layout/generic/nsBlockFrame.cpp
@@ -2574,6 +2574,12 @@ IsMarginZero(nsStyleUnit aUnit, nsStyleCoord &aCoord)
 /* virtual */ PRBool
 nsBlockFrame::IsSelfEmpty()
 {
+  // Blocks which are margin-roots (including inline-blocks) cannot be treated
+  // as empty for margin-collapsing and other purposes. They're more like
+  // replaced elements.
+  if (GetStateBits() & NS_BLOCK_MARGIN_ROOT)
+    return PR_FALSE;
+
   const nsStylePosition* position = GetStylePosition();
 
   switch (position->mMinHeight.GetUnit()) {