fixed bug where empty trash wasn't showing up

src/left_main.php

@@ -54,8 +54,8 @@
          $line .= "&nbsp;<FONT FACE=\"Arial,Helvetica\" SIZE=2>($numUnseen)</FONT>";
       }
 
-      if (($move_to_trash == true) && (trim($mailbox) == $trash_folder)) {
-         $urlMailbox = urlencode($mailbox);
+      if (($move_to_trash == true) && (trim($real_box) == $trash_folder)) {
+         $urlMailbox = urlencode($real_box);
          $line .= "<FONT FACE=\"Arial,Helvetica\" SIZE=2>";
          $line .= "&nbsp;&nbsp;&nbsp;&nbsp;(<B><A HREF=\"empty_trash.php?numMessages=$numMessages&mailbox=$urlMailbox\" TARGET=right style=\"text-decoration:none\">empty</A></B>)";
          $line .= "</FONT></a>\n";