diff --git a/webui/view/theme/default/assets/css/metro-bootstrap.css b/webui/view/theme/default/assets/css/metro-bootstrap.css
index 5154d384..0e5ecb5c 100644
--- a/webui/view/theme/default/assets/css/metro-bootstrap.css
+++ b/webui/view/theme/default/assets/css/metro-bootstrap.css
@@ -1665,7 +1665,7 @@ html,body{height:auto !important;height:100%;min-height:100%;}
 #searchcontainer #button_expert{width:40%;}
 #searchcontainer #button_audit{width:100%;}
 #searchcontainer #button_search,#searchcontainer #button_options{width:30%;}
-#mainscreen{position:absolute;top:120px;right:20px;bottom:20px;left:20px;min-width:320px;z-index:-1;}
+#mainscreen{position:absolute;top:120px;right:20px;bottom:20px;left:20px;min-width:320px;z-index:0;}
 #mailleftcontainer{position:absolute;top:0;left:0;bottom:0;width:195px;}
 #mailboxlist-container{position:absolute;top:0;left:0;width:100%;bottom:0;border:1px solid #999999;border-top:none;background-color:#f9f9f9;overflow:hidden;}
 .boxlistcontent{position:absolute;top:0px;bottom:34px;left:0;right:0;width:100%;overflow-y:auto;overflow-x:hidden;height:auto;}