Fix for 144141. Force folder pane to open if it's collapsed at startup. r=naving, sr=mscott.

mailnews/base/resources/content/msgMail3PaneWindow.js

@@ -691,8 +691,27 @@ function UpgradeFolderPaneUI()
   }
 }
 
+// This is a workaround fix for bug 144141 since it's too risky to change code
+// to load the thread pane window with msgs when folder pane is collapsed/closed
+// at startup (since this has never worked before). The workaround is to force
+// folder pane open (with default width) at startup if it was collapsed.
+function ForceFolderPaneOpen()
+{
+  if (! sidebar_is_collapsed())
+    return false;
+
+  var sidebar_box = document.getElementById('sidebar-box');
+  var sidebar_splitter = document.getElementById('sidebar-splitter');
+
+  sidebar_box.removeAttribute('collapsed');
+  sidebar_box.removeAttribute('width'); // use default width
+  sidebar_splitter.removeAttribute('state');
+  return true;
+}
+
 function OnLoadFolderPane()
 {
+    ForceFolderPaneOpen();
     UpgradeFolderPaneUI();
 
     var folderUnreadCol = document.getElementById("folderUnreadCol");