fix style bug of TagSelect

Author: Rokt33r

browser/styles/main/ArticleDetail.styl

@@ -257,9 +257,10 @@ infoButton()
           width 150px
           max-height 150px
           background-color white
-          z-index 5
+          z-index 50
           border 1px solid borderColor
           border-radius 5px
+          overflow-y auto
           &>button
             width 100%
             display block