Fix bug where it wasn't possible to scroll folders list in Edge (#5750)

CHANGELOG

@@ -6,6 +6,7 @@ CHANGELOG Roundcube Webmail
 - Fix conflict with _gid cookie of Google Analytics (#5748)
 - Print error from CLI scripts when system/exec function is disabled (#5744)
 - Fix bug where comment notation within style tag would cause the whole style to be ignored (#5747)
+- Fix bug where it wasn't possible to scroll folders list in Edge (#5750)
 
 RELEASE 1.3-rc
 --------------

skins/larry/mail.css

@@ -16,7 +16,7 @@
 	left: 0;
 	width: 200px;
 	bottom: 0;
-	z-index: 2;
+	z-index: 1; /* fixes scrolling in Edge (#5750) */
 }
 
 #mailview-right {
@@ -25,7 +25,6 @@
 	left: 212px;
 	right: 0;
 	bottom: 0;
-	z-index: 3;
 }
 
 #mailview-right.fullwidth {
@@ -199,7 +198,6 @@ html.mozilla #mailboxlist > li:first-child {
 	left: 0;
 	height: 40px;
 	white-space: nowrap;
-	z-index: 10;
 }
 
 #messagetoolbar.fullwidth {