Bug 973502 - constrain max width of Australis bookmarks menu, r=Unfocused

--HG--
extra : rebase_source : b515c86803e839aed1e3834c38e83c00c7419762

browser/themes/shared/customizableui/panelUIOverlay.inc.css

@@ -143,6 +143,7 @@
 }
 
 #PanelUI-contents,
+#BMB_bookmarksPopup,
 .panel-mainview:not([panelid="PanelUI-popup"]) {
   max-width: @menuPanelWidth@;
 }