Shrink new tab context menu

chrome/userChrome.css

 /* Hide extra manage bookmarks button */
 #BMB_bookmarksPopup #BMB_bookmarksShowAll { display: none; }
 
+/* Hide first separator in new tab context menu */
+#new-tab-button-popup > menuseparator:nth-of-type(1) { display: none; }
+
 /* Shrink bookmark separators */
 #PlacesToolbarItems > toolbarseparator::before {
 	filter: opacity(0.3);