Revert "another attempt to workaround against feedtree scroll issues"

This reverts commit 9f8b2e6ea8.

tt-rss.css

@@ -768,7 +768,7 @@ div.fatalError textarea {
 	border-left-width : 0px;
 	border-bottom-width : 0px;
 	border-top-width : 0px;
-	overflow : auto;
+	overflow : hidden;
 }
 
 #headlines-wrap-inner {
@@ -777,10 +777,6 @@ div.fatalError textarea {
 	border-width : 0px;
 }
 
-#feedTree {
-	overflow : visible;
-}
-
 #headlines-frame {
 	padding : 0px;
 	border-color : #88b0f0;