diff --git a/mail/inc/class.mail_hooks.inc.php b/mail/inc/class.mail_hooks.inc.php
index 78ee57887e..dc46401bed 100644
--- a/mail/inc/class.mail_hooks.inc.php
+++ b/mail/inc/class.mail_hooks.inc.php
@@ -436,9 +436,10 @@ class mail_hooks
 				'name' => 'previewPane',
 				'values' => array(
 					'vertical' => lang('show vertical'),
+					'allColumns' => lang('show vertical with all columns'),
 					'fixed' => lang('show horizontal'),
 					'expand' => lang('show horizontal, hide if none selected'),
-					'hide' => lang('never show'),
+					'hide' => lang('never show')
 				),
 				'default' => 'vertical',
 				'reload' => true
diff --git a/mail/inc/class.mail_ui.inc.php b/mail/inc/class.mail_ui.inc.php
index 517401fa40..ef0c0f6958 100644
--- a/mail/inc/class.mail_ui.inc.php
+++ b/mail/inc/class.mail_ui.inc.php
@@ -622,6 +622,10 @@ class mail_ui
 			case "vertical":
 				$etpl->setElementAttribute('mailSplitter', 'orientation', 'v');
 				break;
+			case "allColumns":
+				$etpl->setElementAttribute('mailSplitter', 'orientation', 'v');
+				$etpl->setElementAttribute('nm', 'template', 'mail.index.rows.horizental');
+				break;
 			case "expand":
 			case "fixed":
 				$etpl->setElementAttribute('mailSplitter', 'orientation', 'h');