new file

chrome/scrollable_urlbar_popup.css

@@ -0,0 +1,10 @@
+/* Makes the urlbar dropdown scrollable */
+/* Modify the pref browser.urlbar.maxRichResults to set how many results should be shown */
+
+/* This must NOT be loaded in xul namespace */
+/* Either load this file using @import or otherwise make sure that the namespace is correctly set */
+
+@namespace html url("http://www.w3.org/1999/xhtml");
+
+html|div#urlbarView-results,
+html|div#urlbar-results{ max-height: 400px; overflow-y: auto; scrollbar-color: currentColor transparent; scrollbar-width: thin }