--- /roundcube/config/main.inc.php	Fri Jan 21 09:26:59 2011
+++ /roundcube/config/main.inc.php	Wed Jan 19 16:40:24 2011
@@ -548,0 +549,5 @@
+// Enable or disable attachment preview window
+// true = enable attachment preview window
+// false = disable attachment preview window
+$rcmail_config['attach_preview_window'] = false;
+