diff --git a/mailnews/addrbook/resources/content/addressbook.xul b/mailnews/addrbook/resources/content/addressbook.xul
index 3b6ca25f2c52..17ec28469eaf 100644
--- a/mailnews/addrbook/resources/content/addressbook.xul
+++ b/mailnews/addrbook/resources/content/addressbook.xul
@@ -250,7 +250,7 @@ Rights Reserved.
 	<box align="horizontal" flex="100%" style="min-width:150px">
 		<!-- sidebar with dir tree -->
 		<box id="sidebar-box">
-			<splitter class="sidebar-main-header" collapse="after">
+			<splitter class="sidebarheader-main" collapse="after">
 				<text style="min-width:1px" value="&addressbook-sidebar-header.label;"/>
 			</splitter>
 			
diff --git a/mailnews/base/resources/content/messenger.xul b/mailnews/base/resources/content/messenger.xul
index a0f9f7360e20..0816905ea2d9 100644
--- a/mailnews/base/resources/content/messenger.xul
+++ b/mailnews/base/resources/content/messenger.xul
@@ -311,7 +311,7 @@ Rights Reserved.
 
 	<box align="horizontal" style="height:100px" flex="1">
 		<box id="sidebar-box">
-			<splitter class="sidebar-main-header" collapse="after" persist="state">
+			<splitter class="sidebarheader-main" collapse="after" persist="state">
 				<text value="&mail-sidebar-header.label;"/>
 			</splitter>
 			<tree id="folderTree" style="width:100px; height: 600px;" flex="1" context="folderPaneContext"/>
diff --git a/xpfe/components/sidebar/resources/preview.xul b/xpfe/components/sidebar/resources/preview.xul
index 7ba8c49655f2..5c388e15865f 100644
--- a/xpfe/components/sidebar/resources/preview.xul
+++ b/xpfe/components/sidebar/resources/preview.xul
@@ -37,7 +37,7 @@
 
   <script src="chrome://communicator/content/sidebar/preview.js" />
 
-  <box id="paneltitle" class="texttab sidebar-tab"
+  <box id="paneltitle" class="texttab texttab-sidebar"
     align="left" selected="true"/>
 
 <!--  <iframe id="previewframe" type="content" src="about:blank" flex="1"/>-->
diff --git a/xpfe/components/sidebar/resources/sidebarOverlay.css b/xpfe/components/sidebar/resources/sidebarOverlay.css
index aaa540e2f63a..9091fa36c67c 100644
--- a/xpfe/components/sidebar/resources/sidebarOverlay.css
+++ b/xpfe/components/sidebar/resources/sidebarOverlay.css
@@ -43,7 +43,7 @@
         url("chrome://communicator/skin/sidebar/sidebar-bottomright-cap.gif"); 
 }
 
-splitter#sidebar-splitter > grippy {
+#sidebar-splitter > grippy {
     margin: 0px;
     padding: 0px;
     border: 2px solid #003366;
@@ -54,46 +54,46 @@ splitter#sidebar-splitter > grippy {
     background-position: 50% 50%;
 }
 
-splitter#sidebar-splitter > grippy:hover,
-splitter#sidebar-splitter > grippy:active {
+#sidebar-splitter > grippy:hover,
+#sidebar-splitter > grippy:active {
     background-color: #99CCFF;
     background-image:
        url("chrome://communicator/skin/sidebar/sbgrippy-left-hover.gif"); 
 }
 
-splitter#sidebar-splitter[collapsed="true"] > grippy {
+#sidebar-splitter[collapsed="true"] > grippy {
     background-image:
        url("chrome://communicator/skin/sidebar/sbgrippy-right.gif"); 
 }
 
-splitter#sidebar-splitter[collapsed="true"] > grippy:hover,
-splitter#sidebar-splitter[collapsed="true"] > grippy:active {
+#sidebar-splitter[collapsed="true"] > grippy:hover,
+#sidebar-splitter[collapsed="true"] > grippy:active {
     background-image:
        url("chrome://communicator/skin/sidebar/sbgrippy-right-hover.gif"); 
 }
 
-image#sidebar-status-grippy {
+#sidebar-status-grippy {
     padding: 2px 2px 2px 0px;
     background-color: #003366;
     background-image:
        url("chrome://communicator/skin/sidebar/sidebar-open.gif"); 
 }
-image#sidebar-status-grippy:hover {
+#sidebar-status-grippy:hover {
     background-image:
        url("chrome://communicator/skin/sidebar/sidebar-open-hover.gif"); 
 }
-image#sidebar-status-grippy[open="true"] {
+#sidebar-status-grippy[open="true"] {
     background-image:
        url("chrome://communicator/skin/sidebar/sidebar-close.gif"); 
 }
-image#sidebar-status-grippy[open="true"]:hover {
+#sidebar-status-grippy[open="true"]:hover {
     background-image:
        url("chrome://communicator/skin/sidebar/sidebar-close-hover.gif"); 
 }
 
 /**/
 
-box#sidebar-box {
+#sidebar-box {
     margin-top: 1px;
     width: 162px;
     min-height: 1px;
@@ -103,94 +103,79 @@ box#sidebar-box {
     border-bottom: 8px solid #003366;
 }
 
-box#sidebar-panels {
+#sidebar-panels {
     min-width: 1px;
     min-height: 1px;
     margin-top: 1px;
 }
 
-text.loading-image {
+.text-panel-loading {
     margin: 5px 0px;
 }
-
-image.loading-image {
+.image-panel-loading {
     margin: 5px;
     list-style-image: url("resource:/res/rdf/loading.gif"); 
 }
 
-iframe.panel-frame {
+.iframe-panel {
     min-width: 1px;
 }
 
 /*
  *    Sidebar and Panel title buttons
  */
-.sidebar-main-header {
-    color: #CCFFFF;
-    background-color: #003366;
-    border: 0px !important;
-    padding-left: 4px;
-    min-width: 1px;
-}
-.sidebar-main-header > text {
-    font-weight: bold;
-    margin: 2px;
-}
-
-menu#sidebar-panel-picker:hover {
-    background-color: #336699;
-}
-menu#sidebar-panel-picker:hover {
-    background-color: #336699;
-}
-menu#sidebar-panel-picker > .menu-right {
-    list-style-image: url("chrome://global/skin/toolbar-menu-arrow.gif");
-    padding-right: 2px;
-}
-menu#sidebar-panel-picker > .menu-text {
-    color: #CCFFFF;
-    padding-left: 4px;
-}
-menu#sidebar-panel-picker > .menu-accel {
-    display: none;
-}
-
 sidebarheader[type="box"] {
     behavior: url(chrome://global/content/globalBindings.xml#sidebar-header-box);
 }
-
 sidebarheader[type="splitter"] {
     behavior: url(chrome://global/content/globalBindings.xml#sidebar-header-splitter);
     /* a vertical splitter */
     cursor: n-resize;
 }
 
-box.texttab.sidebar-tab {
+.sidebarheader-main {
+    color: #CCFFFF;
+    background-color: #003366;
+    border: 0px !important;
+    padding-left: 4px;
+    min-width: 1px;
+}
+.sidebarheader-main > text {
+    font-weight: bold;
+    margin: 2px;
+}
+
+#sidebar-panel-picker:hover {
+    background-color: #336699;
+}
+#sidebar-panel-picker > .menu-right {
+    list-style-image: url("chrome://global/skin/toolbar-menu-arrow.gif");
+    padding-right: 2px;
+}
+#sidebar-panel-picker > .menu-text {
+    color: #CCFFFF;
+    padding-left: 4px;
+}
+#sidebar-panel-picker > .menu-accel {
+    display: none;
+}
+
+.texttab.texttab-sidebar {
     background-color: #CCCCCC;
     padding: 0px;
     margin: 0px;
 }
-box.texttab.sidebar-tab[top-panel="true"],
-box.texttab.sidebar-tab[first-panel-after-selected="true"] {
+.texttab.texttab-sidebar[top-panel="true"],
+.texttab.texttab-sidebar[first-panel-after-selected="true"] {
     background-color: white;
 }
-
-box.texttab.sidebar-tab > .remain-space {
+.texttab.texttab-sidebar > .remain-space {
     width: 30px;
     min-width: 1px;
 }
-box.texttab.sidebar-tab[last-panel="true"] > .remain-space {
+.texttab.texttab-sidebar[last-panel="true"] > .remain-space {
   border-bottom: none;
 }
-box.texttab.sidebar-tab[last-panel="true"][selected="true"] > .remain-space {
+.texttab.texttab-sidebar[last-panel="true"][selected="true"] > .remain-space {
   border-bottom: 1px solid black;
 }
-
-*[hidden="true"] {
-    display: none;
-}
-
-*[collapsed="true"] {
-    visibility: collapse;
-}
-
diff --git a/xpfe/components/sidebar/resources/sidebarOverlay.xul b/xpfe/components/sidebar/resources/sidebarOverlay.xul
index 2278d65a372b..f39a5d63ca8d 100644
--- a/xpfe/components/sidebar/resources/sidebarOverlay.xul
+++ b/xpfe/components/sidebar/resources/sidebarOverlay.xul
@@ -1,4 +1,4 @@
-<?xml version="1.0"?> <!-- -*- Mode: SGML; indent-tabs-mode: nil -*- -->
+<?xml version="1.0"?> <!-- -*- Mode: HTML; indent-tabs-mode: nil -*- -->
 <!--
 
   The contents of this file are subject to the Netscape Public License
@@ -29,7 +29,7 @@
   <!-- Overlay the sidebar panels -->
   <box id="sidebar-box" align="vertical"
     persist="hidden width collapsed">
-    <sidebarheader id="sidebar-title-box" class="sidebar-main-header"
+    <sidebarheader id="sidebar-title-box" class="sidebarheader-main"
       value="&sidebar.panels.label;" persist="hidden state"
       collapse="after" onmouseup="PersistHeight();">
       <menu id="sidebar-panel-picker" class="standard" crop="right"
@@ -59,7 +59,7 @@
       persist='last-selected-panel height collapsed hidden' flex="1*">
       <template id="sidebar-template">
         <rule>
-          <box uri="rdf:*" class="texttab sidebar-tab" align="left" 
+          <box uri="rdf:*" class="texttab texttab-sidebar" align="left" 
             value="rdf:http://home.netscape.com/NC-rdf#title"
             onclick="SidebarSelectPanel(this)"
             exclude="rdf:http://home.netscape.com/NC-rdf#exclude"
@@ -67,15 +67,16 @@
           <box uri="rdf:*" flex='1*' hidden="true" orient="vertical">
             <box flex='1' orient="vertical">
               <box orient="horizontal" flex="1" autostretch="never">
-                <image class="loading-image"/>
-                <text class="loading-image" value="&sidebar.loading.label;"/>
+                <image class="image-panel-loading"/>
+                <text class="text-panel-loading"
+                  value="&sidebar.loading.label;"/>
               </box>
               <spring flex="100%"/>
             </box>
-            <iframe class="panel-frame" flex='1*'
+            <iframe class="iframe-panel" flex='1*'
               hidden="true" collapsed="true"
               src="rdf:http://home.netscape.com/NC-rdf#content" />
-            <iframe class="panel-frame" flex='1*'
+            <iframe class="iframe-panel" flex='1*'
               hidden="true" collapsed="true"
               src="rdf:http://home.netscape.com/NC-rdf#content"
               type="content" />