diff --git a/layout/reftests/bugs/513318-1-ref.xul b/layout/reftests/bugs/513318-1-ref.xul
new file mode 100644
index 000000000000..40b12a6074a4
--- /dev/null
+++ b/layout/reftests/bugs/513318-1-ref.xul
@@ -0,0 +1,5 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="XUL Layout"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+</window>
diff --git a/layout/reftests/bugs/513318-1.xul b/layout/reftests/bugs/513318-1.xul
new file mode 100644
index 000000000000..a1b758629cfa
--- /dev/null
+++ b/layout/reftests/bugs/513318-1.xul
@@ -0,0 +1,51 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="XUL Layout"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+    <vbox style="overflow:auto; height:100px">
+		<hbox style="visibility:collapse">
+			<label>
+				<label value="0"/>
+				<label value="1"/>
+				<label value="2"/>
+				<label value="3"/>
+				<label value="4"/>
+				<label value="5"/>
+				<label value="6"/>
+				<label value="7"/>
+				<label value="8"/>
+				<label value="9"/>
+				<label value="0"/>
+				<label value="1"/>
+				<label value="2"/>
+				<label value="3"/>
+				<label value="4"/>
+				<label value="5"/>
+				<label value="6"/>
+				<label value="7"/>
+				<label value="8"/>
+				<label value="9"/>
+				<label value="0"/>
+				<label value="1"/>
+				<label value="2"/>
+				<label value="3"/>
+				<label value="4"/>
+				<label value="5"/>
+				<label value="6"/>
+				<label value="7"/>
+				<label value="8"/>
+				<label value="9"/>
+				<label value="0"/>
+				<label value="1"/>
+				<label value="2"/>
+				<label value="3"/>
+				<label value="4"/>
+				<label value="5"/>
+				<label value="6"/>
+				<label value="7"/>
+				<label value="8"/>
+				<label value="9"/>
+			</label>
+		</hbox>
+	</vbox>
+</window>
diff --git a/layout/reftests/bugs/513318-2-ref.xul b/layout/reftests/bugs/513318-2-ref.xul
new file mode 100644
index 000000000000..647545792d1e
--- /dev/null
+++ b/layout/reftests/bugs/513318-2-ref.xul
@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="XUL Layout"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        xmlns:html="http://www.w3.org/1999/xhtml">
+    <vbox style="overflow:auto; height:200px">
+		<html:span style="color:blue;">Hello Kitty</html:span>
+	</vbox>
+</window>
diff --git a/layout/reftests/bugs/513318-2.xul b/layout/reftests/bugs/513318-2.xul
new file mode 100644
index 000000000000..9734de16b297
--- /dev/null
+++ b/layout/reftests/bugs/513318-2.xul
@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="XUL Layout"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        xmlns:html="http://www.w3.org/1999/xhtml">
+    <vbox style="overflow:auto; height:200px">
+		<html:span style="color:blue; text-shadow:0px 300px;">Hello Kitty</html:span>
+	</vbox>
+</window>
diff --git a/layout/reftests/bugs/513318-3-ref.xul b/layout/reftests/bugs/513318-3-ref.xul
new file mode 100644
index 000000000000..bec47d615466
--- /dev/null
+++ b/layout/reftests/bugs/513318-3-ref.xul
@@ -0,0 +1,8 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="XUL Layout"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+    <vbox style="overflow:auto; height:200px">
+		<label style="color:blue;" value="Hello Kitty" />
+	</vbox>
+</window>
diff --git a/layout/reftests/bugs/513318-3.xul b/layout/reftests/bugs/513318-3.xul
new file mode 100644
index 000000000000..dbe74638fe12
--- /dev/null
+++ b/layout/reftests/bugs/513318-3.xul
@@ -0,0 +1,8 @@
+<?xml version="1.0"?>
+<?xml-stylesheet href="chrome://global/skin" type="text/css"?>
+<window title="XUL Layout"
+        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
+    <vbox style="overflow:auto; height:200px">
+		<label style="color:blue; text-shadow:0px 300px;" value="Hello Kitty" />
+	</vbox>
+</window>
diff --git a/layout/reftests/bugs/reftest.list b/layout/reftests/bugs/reftest.list
index 7c323eaee0e0..cdef793d9d0b 100644
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@@ -1317,3 +1317,6 @@ fails-if(MOZ_WIDGET_TOOLKIT!="cocoa") == 488692-1.html 488692-1-ref.html # needs
 == 513153-1b.html 513153-1-ref.html
 == 513153-2a.html 513153-2-ref.html
 == 513153-2b.html 513153-2-ref.html
+== 513318-1.xul 513318-1-ref.xul
+!= 513318-2.xul 513318-2-ref.xul
+!= 513318-3.xul 513318-3-ref.xul
diff --git a/layout/xul/base/src/nsBox.cpp b/layout/xul/base/src/nsBox.cpp
index 333038a86211..ab589899f742 100644
--- a/layout/xul/base/src/nsBox.cpp
+++ b/layout/xul/base/src/nsBox.cpp
@@ -591,7 +591,7 @@ nsBox::SyncLayout(nsBoxLayoutState& aState)
     rect = GetOverflowRect();
   }
   else {
-    if (!DoesClipChildren()) {
+    if (!DoesClipChildren() && !IsCollapsed(aState)) {
       // See if our child frames caused us to overflow after being laid
       // out. If so, store the overflow area.  This normally can't happen
       // in XUL, but it can happen with the CSS 'outline' property and