Stop the scrollbar from showing up unnecessarily (vuejs#923)

Author: sscaff1

themes/vue/source/css/_common.styl

@@ -158,7 +158,7 @@ a.button
         display none
         box-sizing border-box
         max-height "calc(100vh - %s)" % $header-height
-        overflow-y scroll
+        overflow-y auto
         position absolute
         top 100%
         right -15px