Land the new vertical 3-pane for thunderbird. Folder pane | Thread Pane | Message pane.

new pref UI for selecting three 3-pane configurations.

mail/components/prefwindow/content/pref-mailnews.xul

@@ -66,9 +66,10 @@
     <caption label="&windowSettings.label;"/>
     <label value="&selectWindowLayout.label;" accesskey="&selectWindowLayout.accesskey;" control="mailPaneConfig"/>
     <hbox align="center" class="indent">
-      <radiogroup id="mailPaneConfig" prefstring="mail.pane_config" orient="horizontal">
+      <radiogroup id="mailPaneConfig" prefstring="mail.pane_config.dynamic" orient="horizontal">
         <radio class="iconic" value="0" id="classic"/>
         <radio class="iconic" value="1" id="wide"/>
+        <radio class="iconic" value="2" id="vertical"/>
       </radiogroup>
     </hbox> 
   </groupbox>

mail/components/prefwindow/jar.mn

@@ -36,3 +36,5 @@ en-US.jar:
 classic.jar:
 +  skin/classic/communicator/pref/pref.css                             (skin/pref.css)
 +  skin/classic/messenger/prefPanels.css                               (skin/prefPanels.css)
+   skin/classic/messenger/icons/winvertical.gif                        (skin/winvertical.gif)
+

mail/components/prefwindow/skin/prefPanels.css

@@ -44,6 +44,12 @@
   list-style-image : url("chrome://messenger/skin/icons/winwide.gif");
 }
 
+#vertical
+{
+  min-height       : 32px;
+  list-style-image : url("chrome://messenger/skin/icons/winvertical.gif");
+}
+
 .expanderButton 
 {
   cursor: pointer;