diff --git a/suite/common/pref/pref-appearance.xul b/suite/common/pref/pref-appearance.xul
index c4a2475ed66b..17960ca8b347 100644
--- a/suite/common/pref/pref-appearance.xul
+++ b/suite/common/pref/pref-appearance.xul
@@ -109,38 +109,5 @@
 	</box>
 </html:form>
 
-<!-- Temporary hack to turn on gfx-rendered widgets -->  
-<html:form>
-	<box align="vertical" style="width: 100%;">
-		<html:fieldset style="width: 100%;">
-    	<html:legend align="left">
-		<html:div>&widgetRendering.label;</html:div> 
-		</html:legend>
-     	    <box align="horizontal">
-		<html:div>
-				<html:input name="widgetRendering" type="radio" id="pref:0:int:nglayout.widget.mode" />
-				<html:label for="pref:0:int:nglayout.widget.mode" accesskey="n" tabindex="0">
-				&nativeWidgets.label;
-				</html:label>
-			</html:div>
-			<html:div>
-				<html:input name="widgetRendering" type="radio" id="pref:1:int:nglayout.widget.mode" />
-				<html:label for="pref:1:int:nglayout.widget.mode" accesskey="n" tabindex="0">
-				&partialGfxWidgets.label;
-				</html:label>
-			</html:div>
-			<html:div>
-				<html:input name="widgetRendering" type="radio" id="pref:2:int:nglayout.widget.mode" />
-				<html:label for="pref:2:int:nglayout.widget.mode" accesskey="g" tabindex="0">
-				&gfxWidgets.label;
-				</html:label>
-			</html:div>  
-          </box> 
-		</html:fieldset>
-	</box>
-</html:form> 
-
-
-
 </html:div>
 </window>
diff --git a/suite/common/pref/pref-debug.xul b/suite/common/pref/pref-debug.xul
new file mode 100644
index 000000000000..dc2f9701dddf
--- /dev/null
+++ b/suite/common/pref/pref-debug.xul
@@ -0,0 +1,94 @@
+<?xml version="1.0"?> 
+<!--
+   The contents of this file are subject to the Netscape Public
+   License Version 1.1 (the "License"); you may not use this file
+   except in compliance with the License. You may obtain a copy of
+   the License at http://www.mozilla.org/NPL/
+    
+   Software distributed under the License is distributed on an "AS
+   IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+   implied. See the License for the specific language governing
+   rights and limitations under the License.
+    
+   The Original Code is Mozilla Communicator client code, released
+   March 31, 1998.
+   
+   The Initial Developer of the Original Code is Netscape
+   Communications Corporation. Portions created by Netscape are
+   Copyright (C) 1998-1999 Netscape Communications Corporation. All
+   Rights Reserved.
+   
+   Contributor(s): 
+  -->
+<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
+
+<!DOCTYPE window SYSTEM "chrome://pref/locale/pref-debug.dtd" >
+
+<window xmlns:html="http://www.w3.org/TR/REC-html40"
+		xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="return StartUp('Debug');"  align="horizontal" title="&window.title;">
+
+<html:script language="javascript" src="chrome://pref/content/PrefsWindow.js"/>
+ <html:div flex="100%">
+	<box id="header" style="width:100%" align="horizontal">  
+		  <spring style="width:20px"/>
+		  <html:div style="vertical-align: middle;">
+		  <html:B>&lHeader;</html:B>
+		  </html:div>
+   		  <spring flex="100%"/>
+		  <html:div>&rHeader;</html:div>
+		  <spring style="width:5px"/> 
+	</box>
+	
+	<!-- Temporary hack to turn on gfx-rendered widgets -->  
+<html:form>
+	<box align="vertical" style="width: 100%;">
+		<html:fieldset style="width: 100%;">
+    	<html:legend align="left">
+		<html:div>&widgetRendering.label;</html:div> 
+		</html:legend>
+     	    <box align="horizontal">
+		<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:0:int:nglayout.widget.mode" />
+				<html:label for="pref:0:int:nglayout.widget.mode" accesskey="n" tabindex="0">
+				&nativeWidgets.label;
+				</html:label>
+			</html:div>
+			<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:1:int:nglayout.widget.mode" />
+				<html:label for="pref:1:int:nglayout.widget.mode" accesskey="n" tabindex="0">
+				&partialGfxWidgets.label;
+				</html:label>
+			</html:div>
+			<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:2:int:nglayout.widget.mode" />
+				<html:label for="pref:2:int:nglayout.widget.mode" accesskey="g" tabindex="0">
+				&gfxWidgets.label;
+				</html:label>
+			</html:div>  
+          </box> 
+		</html:fieldset>
+	</box>
+</html:form> 
+
+<!-- Temporary hack to turn on invalidate area flashing -->  
+<html:form>
+	<box align="vertical" style="width: 100%;">
+		<html:fieldset style="width: 100%;">
+    	<html:legend align="left">
+		<html:div>&widgetFlashing.label;</html:div> 
+		</html:legend>
+     	    <box align="horizontal">
+				<html:input type="checkbox" id="pref:0:bool:nglayout.widget.flash_invalidate_areas" />
+				<html:label for="pref:0:bool:nglayout.widget.flash_invalidate_areas" accesskey="n" tabindex="0">
+				&widgetFlashing.label;
+				</html:label>
+          </box> 
+		</html:fieldset>
+	</box>
+</html:form> 
+
+
+</html:div>
+</window>
+
diff --git a/suite/common/pref/preftree.xul b/suite/common/pref/preftree.xul
index 3e59ced58864..afdbd04c51e2 100644
--- a/suite/common/pref/preftree.xul
+++ b/suite/common/pref/preftree.xul
@@ -223,6 +223,13 @@
     </treeitem>
   </treechildren>
 
+    <treeitem open="true">
+      <treerow>       
+        <treecell name="chrome://pref/content/pref-debug.xul"><treeindentation/>&debug.label;</treecell>
+      </treerow>
+
+    </treeitem>
+
 </tree>
 
 </html:div>
diff --git a/suite/debugQA/content/pref-debug.xul b/suite/debugQA/content/pref-debug.xul
new file mode 100644
index 000000000000..dc2f9701dddf
--- /dev/null
+++ b/suite/debugQA/content/pref-debug.xul
@@ -0,0 +1,94 @@
+<?xml version="1.0"?> 
+<!--
+   The contents of this file are subject to the Netscape Public
+   License Version 1.1 (the "License"); you may not use this file
+   except in compliance with the License. You may obtain a copy of
+   the License at http://www.mozilla.org/NPL/
+    
+   Software distributed under the License is distributed on an "AS
+   IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+   implied. See the License for the specific language governing
+   rights and limitations under the License.
+    
+   The Original Code is Mozilla Communicator client code, released
+   March 31, 1998.
+   
+   The Initial Developer of the Original Code is Netscape
+   Communications Corporation. Portions created by Netscape are
+   Copyright (C) 1998-1999 Netscape Communications Corporation. All
+   Rights Reserved.
+   
+   Contributor(s): 
+  -->
+<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
+
+<!DOCTYPE window SYSTEM "chrome://pref/locale/pref-debug.dtd" >
+
+<window xmlns:html="http://www.w3.org/TR/REC-html40"
+		xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="return StartUp('Debug');"  align="horizontal" title="&window.title;">
+
+<html:script language="javascript" src="chrome://pref/content/PrefsWindow.js"/>
+ <html:div flex="100%">
+	<box id="header" style="width:100%" align="horizontal">  
+		  <spring style="width:20px"/>
+		  <html:div style="vertical-align: middle;">
+		  <html:B>&lHeader;</html:B>
+		  </html:div>
+   		  <spring flex="100%"/>
+		  <html:div>&rHeader;</html:div>
+		  <spring style="width:5px"/> 
+	</box>
+	
+	<!-- Temporary hack to turn on gfx-rendered widgets -->  
+<html:form>
+	<box align="vertical" style="width: 100%;">
+		<html:fieldset style="width: 100%;">
+    	<html:legend align="left">
+		<html:div>&widgetRendering.label;</html:div> 
+		</html:legend>
+     	    <box align="horizontal">
+		<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:0:int:nglayout.widget.mode" />
+				<html:label for="pref:0:int:nglayout.widget.mode" accesskey="n" tabindex="0">
+				&nativeWidgets.label;
+				</html:label>
+			</html:div>
+			<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:1:int:nglayout.widget.mode" />
+				<html:label for="pref:1:int:nglayout.widget.mode" accesskey="n" tabindex="0">
+				&partialGfxWidgets.label;
+				</html:label>
+			</html:div>
+			<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:2:int:nglayout.widget.mode" />
+				<html:label for="pref:2:int:nglayout.widget.mode" accesskey="g" tabindex="0">
+				&gfxWidgets.label;
+				</html:label>
+			</html:div>  
+          </box> 
+		</html:fieldset>
+	</box>
+</html:form> 
+
+<!-- Temporary hack to turn on invalidate area flashing -->  
+<html:form>
+	<box align="vertical" style="width: 100%;">
+		<html:fieldset style="width: 100%;">
+    	<html:legend align="left">
+		<html:div>&widgetFlashing.label;</html:div> 
+		</html:legend>
+     	    <box align="horizontal">
+				<html:input type="checkbox" id="pref:0:bool:nglayout.widget.flash_invalidate_areas" />
+				<html:label for="pref:0:bool:nglayout.widget.flash_invalidate_areas" accesskey="n" tabindex="0">
+				&widgetFlashing.label;
+				</html:label>
+          </box> 
+		</html:fieldset>
+	</box>
+</html:form> 
+
+
+</html:div>
+</window>
+
diff --git a/suite/debugQA/locales/en-US/pref-debug.dtd b/suite/debugQA/locales/en-US/pref-debug.dtd
new file mode 100644
index 000000000000..c1f7dadebcaf
--- /dev/null
+++ b/suite/debugQA/locales/en-US/pref-debug.dtd
@@ -0,0 +1,15 @@
+<!-- extracted from content/pref-debug.xul -->
+
+<!ENTITY window.title "Debug">
+
+<!ENTITY lHeader "Debug">
+<!ENTITY rHeader "Layout and Rendering debugging preferences">
+
+<!-- Debug: Turn on gfx-rendered widgets -->
+<!ENTITY widgetRendering.label "Debug: Widget rendering">
+<!ENTITY nativeWidgets.label "native">
+<!ENTITY partialGfxWidgets.label "partial-gfx">
+<!ENTITY gfxWidgets.label "gfx">
+
+<!-- Debug: Flash Invalidate() areas -->
+<!ENTITY widgetFlashing.label "Flash Invalidate() Areas">
diff --git a/suite/locales/en-US/chrome/common/pref/pref-appearance.dtd b/suite/locales/en-US/chrome/common/pref/pref-appearance.dtd
index 627cea5c571b..509bf4dda491 100644
--- a/suite/locales/en-US/chrome/common/pref/pref-appearance.dtd
+++ b/suite/locales/en-US/chrome/common/pref/pref-appearance.dtd
@@ -13,9 +13,3 @@
 <!ENTITY picsNtextRadio.label "Pictures and Text">
 <!ENTITY picsOnlyRadio.label "Pictures Only">
 <!ENTITY textonlyRadio.label "Text Only">
-
-<!-- Debug: Turn on gfx-rendered widgets -->
-<!ENTITY widgetRendering.label "Debug: Widget rendering">
-<!ENTITY nativeWidgets.label "native">
-<!ENTITY partialGfxWidgets.label "partial-gfx">
-<!ENTITY gfxWidgets.label "gfx">
diff --git a/suite/locales/en-US/chrome/common/pref/pref-debug.dtd b/suite/locales/en-US/chrome/common/pref/pref-debug.dtd
new file mode 100644
index 000000000000..c1f7dadebcaf
--- /dev/null
+++ b/suite/locales/en-US/chrome/common/pref/pref-debug.dtd
@@ -0,0 +1,15 @@
+<!-- extracted from content/pref-debug.xul -->
+
+<!ENTITY window.title "Debug">
+
+<!ENTITY lHeader "Debug">
+<!ENTITY rHeader "Layout and Rendering debugging preferences">
+
+<!-- Debug: Turn on gfx-rendered widgets -->
+<!ENTITY widgetRendering.label "Debug: Widget rendering">
+<!ENTITY nativeWidgets.label "native">
+<!ENTITY partialGfxWidgets.label "partial-gfx">
+<!ENTITY gfxWidgets.label "gfx">
+
+<!-- Debug: Flash Invalidate() areas -->
+<!ENTITY widgetFlashing.label "Flash Invalidate() Areas">
diff --git a/suite/locales/en-US/chrome/common/pref/preftree.dtd b/suite/locales/en-US/chrome/common/pref/preftree.dtd
index 02bd37888fe5..d37b9adebd3c 100644
--- a/suite/locales/en-US/chrome/common/pref/preftree.dtd
+++ b/suite/locales/en-US/chrome/common/pref/preftree.dtd
@@ -23,3 +23,4 @@
 <!ENTITY cache.label "Cache">
 <!ENTITY proxies.label "Proxies">
 <!ENTITY smart.label "Smart Update">
+<!ENTITY debug.label "Debug">
diff --git a/xpfe/components/prefwindow/resources/content/MANIFEST b/xpfe/components/prefwindow/resources/content/MANIFEST
index 1877c421bc3f..73f84f8cc751 100644
--- a/xpfe/components/prefwindow/resources/content/MANIFEST
+++ b/xpfe/components/prefwindow/resources/content/MANIFEST
@@ -4,6 +4,7 @@ pref-applications.xul
 pref-cache.xul
 pref-colors.xul
 pref-composer.xul
+pref-debug.xul
 pref-download.xul
 pref-fonts.xul
 pref-languages.xul
diff --git a/xpfe/components/prefwindow/resources/content/Makefile.in b/xpfe/components/prefwindow/resources/content/Makefile.in
index 51c1c6fdce43..59baf79607eb 100644
--- a/xpfe/components/prefwindow/resources/content/Makefile.in
+++ b/xpfe/components/prefwindow/resources/content/Makefile.in
@@ -27,12 +27,16 @@ include $(topsrcdir)/config/config.mk
 include $(topsrcdir)/config/rules.mk
 
 EXPORT_RESOURCE_CONTENT = \
+	$(srcdir)/PrefsWindow.html \
+	$(srcdir)/PrefsWindow.js \
+	$(srcdir)/PrefsWindow.xul \
 	$(srcdir)/pref-advanced.xul \
 	$(srcdir)/pref-appearance.xul \
 	$(srcdir)/pref-applications.xul \
 	$(srcdir)/pref-cache.xul \
 	$(srcdir)/pref-colors.xul \
 	$(srcdir)/pref-composer.xul \
+	$(srcdir)/pref-debug.xul \
 	$(srcdir)/pref-download.xul \
 	$(srcdir)/pref-fonts.xul \
 	$(srcdir)/pref-languages.xul \
@@ -43,9 +47,6 @@ EXPORT_RESOURCE_CONTENT = \
 	$(srcdir)/pref-select.html \
 	$(srcdir)/pref-smart_browsing.xul \
 	$(srcdir)/pref-smartupdate.xul \
-	$(srcdir)/PrefsWindow.html \
-	$(srcdir)/PrefsWindow.js \
-	$(srcdir)/PrefsWindow.xul \
 	$(srcdir)/preftree.xul \
 	$(NULL)
 
diff --git a/xpfe/components/prefwindow/resources/content/makefile.win b/xpfe/components/prefwindow/resources/content/makefile.win
index 8bda051146f8..9a1636180dc9 100644
--- a/xpfe/components/prefwindow/resources/content/makefile.win
+++ b/xpfe/components/prefwindow/resources/content/makefile.win
@@ -26,6 +26,7 @@ install::
 	$(MAKE_INSTALL) pref-cache.xul  $(DIST)\bin\chrome\pref\content\default
 	$(MAKE_INSTALL) pref-colors.xul  $(DIST)\bin\chrome\pref\content\default
 	$(MAKE_INSTALL) pref-composer.xul  $(DIST)\bin\chrome\pref\content\default
+	$(MAKE_INSTALL) pref-debug.xul  $(DIST)\bin\chrome\pref\content\default
 	$(MAKE_INSTALL) pref-download.xul  $(DIST)\bin\chrome\pref\content\default
 	$(MAKE_INSTALL) pref-fonts.xul  $(DIST)\bin\chrome\pref\content\default
 	$(MAKE_INSTALL) pref-languages.xul  $(DIST)\bin\chrome\pref\content\default
diff --git a/xpfe/components/prefwindow/resources/content/pref-appearance.xul b/xpfe/components/prefwindow/resources/content/pref-appearance.xul
index c4a2475ed66b..17960ca8b347 100644
--- a/xpfe/components/prefwindow/resources/content/pref-appearance.xul
+++ b/xpfe/components/prefwindow/resources/content/pref-appearance.xul
@@ -109,38 +109,5 @@
 	</box>
 </html:form>
 
-<!-- Temporary hack to turn on gfx-rendered widgets -->  
-<html:form>
-	<box align="vertical" style="width: 100%;">
-		<html:fieldset style="width: 100%;">
-    	<html:legend align="left">
-		<html:div>&widgetRendering.label;</html:div> 
-		</html:legend>
-     	    <box align="horizontal">
-		<html:div>
-				<html:input name="widgetRendering" type="radio" id="pref:0:int:nglayout.widget.mode" />
-				<html:label for="pref:0:int:nglayout.widget.mode" accesskey="n" tabindex="0">
-				&nativeWidgets.label;
-				</html:label>
-			</html:div>
-			<html:div>
-				<html:input name="widgetRendering" type="radio" id="pref:1:int:nglayout.widget.mode" />
-				<html:label for="pref:1:int:nglayout.widget.mode" accesskey="n" tabindex="0">
-				&partialGfxWidgets.label;
-				</html:label>
-			</html:div>
-			<html:div>
-				<html:input name="widgetRendering" type="radio" id="pref:2:int:nglayout.widget.mode" />
-				<html:label for="pref:2:int:nglayout.widget.mode" accesskey="g" tabindex="0">
-				&gfxWidgets.label;
-				</html:label>
-			</html:div>  
-          </box> 
-		</html:fieldset>
-	</box>
-</html:form> 
-
-
-
 </html:div>
 </window>
diff --git a/xpfe/components/prefwindow/resources/content/pref-debug.xul b/xpfe/components/prefwindow/resources/content/pref-debug.xul
new file mode 100644
index 000000000000..dc2f9701dddf
--- /dev/null
+++ b/xpfe/components/prefwindow/resources/content/pref-debug.xul
@@ -0,0 +1,94 @@
+<?xml version="1.0"?> 
+<!--
+   The contents of this file are subject to the Netscape Public
+   License Version 1.1 (the "License"); you may not use this file
+   except in compliance with the License. You may obtain a copy of
+   the License at http://www.mozilla.org/NPL/
+    
+   Software distributed under the License is distributed on an "AS
+   IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
+   implied. See the License for the specific language governing
+   rights and limitations under the License.
+    
+   The Original Code is Mozilla Communicator client code, released
+   March 31, 1998.
+   
+   The Initial Developer of the Original Code is Netscape
+   Communications Corporation. Portions created by Netscape are
+   Copyright (C) 1998-1999 Netscape Communications Corporation. All
+   Rights Reserved.
+   
+   Contributor(s): 
+  -->
+<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
+
+<!DOCTYPE window SYSTEM "chrome://pref/locale/pref-debug.dtd" >
+
+<window xmlns:html="http://www.w3.org/TR/REC-html40"
+		xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
+        onload="return StartUp('Debug');"  align="horizontal" title="&window.title;">
+
+<html:script language="javascript" src="chrome://pref/content/PrefsWindow.js"/>
+ <html:div flex="100%">
+	<box id="header" style="width:100%" align="horizontal">  
+		  <spring style="width:20px"/>
+		  <html:div style="vertical-align: middle;">
+		  <html:B>&lHeader;</html:B>
+		  </html:div>
+   		  <spring flex="100%"/>
+		  <html:div>&rHeader;</html:div>
+		  <spring style="width:5px"/> 
+	</box>
+	
+	<!-- Temporary hack to turn on gfx-rendered widgets -->  
+<html:form>
+	<box align="vertical" style="width: 100%;">
+		<html:fieldset style="width: 100%;">
+    	<html:legend align="left">
+		<html:div>&widgetRendering.label;</html:div> 
+		</html:legend>
+     	    <box align="horizontal">
+		<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:0:int:nglayout.widget.mode" />
+				<html:label for="pref:0:int:nglayout.widget.mode" accesskey="n" tabindex="0">
+				&nativeWidgets.label;
+				</html:label>
+			</html:div>
+			<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:1:int:nglayout.widget.mode" />
+				<html:label for="pref:1:int:nglayout.widget.mode" accesskey="n" tabindex="0">
+				&partialGfxWidgets.label;
+				</html:label>
+			</html:div>
+			<html:div>
+				<html:input name="widgetRendering" type="radio" id="pref:2:int:nglayout.widget.mode" />
+				<html:label for="pref:2:int:nglayout.widget.mode" accesskey="g" tabindex="0">
+				&gfxWidgets.label;
+				</html:label>
+			</html:div>  
+          </box> 
+		</html:fieldset>
+	</box>
+</html:form> 
+
+<!-- Temporary hack to turn on invalidate area flashing -->  
+<html:form>
+	<box align="vertical" style="width: 100%;">
+		<html:fieldset style="width: 100%;">
+    	<html:legend align="left">
+		<html:div>&widgetFlashing.label;</html:div> 
+		</html:legend>
+     	    <box align="horizontal">
+				<html:input type="checkbox" id="pref:0:bool:nglayout.widget.flash_invalidate_areas" />
+				<html:label for="pref:0:bool:nglayout.widget.flash_invalidate_areas" accesskey="n" tabindex="0">
+				&widgetFlashing.label;
+				</html:label>
+          </box> 
+		</html:fieldset>
+	</box>
+</html:form> 
+
+
+</html:div>
+</window>
+
diff --git a/xpfe/components/prefwindow/resources/content/preftree.xul b/xpfe/components/prefwindow/resources/content/preftree.xul
index 3e59ced58864..afdbd04c51e2 100644
--- a/xpfe/components/prefwindow/resources/content/preftree.xul
+++ b/xpfe/components/prefwindow/resources/content/preftree.xul
@@ -223,6 +223,13 @@
     </treeitem>
   </treechildren>
 
+    <treeitem open="true">
+      <treerow>       
+        <treecell name="chrome://pref/content/pref-debug.xul"><treeindentation/>&debug.label;</treecell>
+      </treerow>
+
+    </treeitem>
+
 </tree>
 
 </html:div>
diff --git a/xpfe/components/prefwindow/resources/locale/en-US/MANIFEST b/xpfe/components/prefwindow/resources/locale/en-US/MANIFEST
index e987453faa17..5b1f63690a0c 100644
--- a/xpfe/components/prefwindow/resources/locale/en-US/MANIFEST
+++ b/xpfe/components/prefwindow/resources/locale/en-US/MANIFEST
@@ -4,6 +4,7 @@ pref-applications.dtd
 pref-cache.dtd
 pref-colors.dtd
 pref-composer.dtd
+pref-debug.dtd
 pref-download.dtd
 pref-fonts.dtd
 pref-languages.dtd
diff --git a/xpfe/components/prefwindow/resources/locale/en-US/Makefile.in b/xpfe/components/prefwindow/resources/locale/en-US/Makefile.in
index 1fdf773f76a5..f1e48af78d9a 100644
--- a/xpfe/components/prefwindow/resources/locale/en-US/Makefile.in
+++ b/xpfe/components/prefwindow/resources/locale/en-US/Makefile.in
@@ -27,12 +27,14 @@ include $(topsrcdir)/config/config.mk
 include $(topsrcdir)/config/rules.mk
 
 EXPORT_RESOURCE_CONTENT = \
+	$(srcdir)/PrefsWindow.dtd \
 	$(srcdir)/pref-advanced.dtd \
 	$(srcdir)/pref-appearance.dtd \
 	$(srcdir)/pref-applications.dtd \
 	$(srcdir)/pref-cache.dtd \
 	$(srcdir)/pref-colors.dtd \
 	$(srcdir)/pref-composer.dtd \
+	$(srcdir)/pref-debug.dtd \
 	$(srcdir)/pref-download.dtd \
 	$(srcdir)/pref-fonts.dtd \
 	$(srcdir)/pref-languages.dtd \
@@ -41,8 +43,7 @@ EXPORT_RESOURCE_CONTENT = \
 	$(srcdir)/pref-proxies.dtd \
 	$(srcdir)/pref-publish.dtd \
 	$(srcdir)/pref-smart_browsing.dtd \
-  $(srcdir)/pref-smartupdate.dtd \
-	$(srcdir)/PrefsWindow.dtd \
+	$(srcdir)/pref-smartupdate.dtd \
 	$(srcdir)/preftree.dtd \
 	$(NULL)
 
diff --git a/xpfe/components/prefwindow/resources/locale/en-US/makefile.win b/xpfe/components/prefwindow/resources/locale/en-US/makefile.win
index 3099968b14c5..b5ace0a0811b 100644
--- a/xpfe/components/prefwindow/resources/locale/en-US/makefile.win
+++ b/xpfe/components/prefwindow/resources/locale/en-US/makefile.win
@@ -27,6 +27,7 @@ install::
 	$(MAKE_INSTALL) pref-colors.dtd  $(DIST)\bin\chrome\pref\locale\en-US
 	$(MAKE_INSTALL) pref-composer.dtd  $(DIST)\bin\chrome\pref\locale\en-US
 	$(MAKE_INSTALL) pref-download.dtd  $(DIST)\bin\chrome\pref\locale\en-US
+	$(MAKE_INSTALL) pref-debug.dtd  $(DIST)\bin\chrome\pref\locale\en-US
 	$(MAKE_INSTALL) pref-fonts.dtd  $(DIST)\bin\chrome\pref\locale\en-US
 	$(MAKE_INSTALL) pref-languages.dtd  $(DIST)\bin\chrome\pref\locale\en-US
 	$(MAKE_INSTALL) pref-navigator.dtd  $(DIST)\bin\chrome\pref\locale\en-US
diff --git a/xpfe/components/prefwindow/resources/locale/en-US/pref-appearance.dtd b/xpfe/components/prefwindow/resources/locale/en-US/pref-appearance.dtd
index 627cea5c571b..509bf4dda491 100644
--- a/xpfe/components/prefwindow/resources/locale/en-US/pref-appearance.dtd
+++ b/xpfe/components/prefwindow/resources/locale/en-US/pref-appearance.dtd
@@ -13,9 +13,3 @@
 <!ENTITY picsNtextRadio.label "Pictures and Text">
 <!ENTITY picsOnlyRadio.label "Pictures Only">
 <!ENTITY textonlyRadio.label "Text Only">
-
-<!-- Debug: Turn on gfx-rendered widgets -->
-<!ENTITY widgetRendering.label "Debug: Widget rendering">
-<!ENTITY nativeWidgets.label "native">
-<!ENTITY partialGfxWidgets.label "partial-gfx">
-<!ENTITY gfxWidgets.label "gfx">
diff --git a/xpfe/components/prefwindow/resources/locale/en-US/pref-debug.dtd b/xpfe/components/prefwindow/resources/locale/en-US/pref-debug.dtd
new file mode 100644
index 000000000000..c1f7dadebcaf
--- /dev/null
+++ b/xpfe/components/prefwindow/resources/locale/en-US/pref-debug.dtd
@@ -0,0 +1,15 @@
+<!-- extracted from content/pref-debug.xul -->
+
+<!ENTITY window.title "Debug">
+
+<!ENTITY lHeader "Debug">
+<!ENTITY rHeader "Layout and Rendering debugging preferences">
+
+<!-- Debug: Turn on gfx-rendered widgets -->
+<!ENTITY widgetRendering.label "Debug: Widget rendering">
+<!ENTITY nativeWidgets.label "native">
+<!ENTITY partialGfxWidgets.label "partial-gfx">
+<!ENTITY gfxWidgets.label "gfx">
+
+<!-- Debug: Flash Invalidate() areas -->
+<!ENTITY widgetFlashing.label "Flash Invalidate() Areas">
diff --git a/xpfe/components/prefwindow/resources/locale/en-US/preftree.dtd b/xpfe/components/prefwindow/resources/locale/en-US/preftree.dtd
index 02bd37888fe5..d37b9adebd3c 100644
--- a/xpfe/components/prefwindow/resources/locale/en-US/preftree.dtd
+++ b/xpfe/components/prefwindow/resources/locale/en-US/preftree.dtd
@@ -23,3 +23,4 @@
 <!ENTITY cache.label "Cache">
 <!ENTITY proxies.label "Proxies">
 <!ENTITY smart.label "Smart Update">
+<!ENTITY debug.label "Debug">