Bug 413066 - Bookmark Contextual Dialog: Tags text field should be self describing. patch from Michael Schonfeld <dev@schonfeld.org>, r=me, ui-r=mconnor, a=beltzner.

browser/components/places/content/editBookmarkOverlay.xul

@@ -161,7 +161,8 @@
                  observes="paneElementsBroadcaster"/>
           <textbox id="editBMPanel_tagsField"
                    onblur="gEditItemOverlay.onTagsFieldBlur();"
-                   observes="paneElementsBroadcaster"/>
+                   observes="paneElementsBroadcaster"
+                   emptytext="&editBookmarkOverlay.tagsEmptyText.label;"/>
           <button id="editBMPanel_tagsSelectorExpander"
                   class="expander-down"
                   tooltiptext="&editBookmarkOverlay.tagsExpanderDown.tooltip;"

browser/locales/en-US/chrome/browser/places/editBookmarkOverlay.dtd

@@ -12,6 +12,7 @@
 <!ENTITY editBookmarkOverlay.expanderUp.tooltip              "Hide">
 <!ENTITY editBookmarkOverlay.tags.label                      "Tags:">
 <!ENTITY editBookmarkOverlay.tags.accesskey                  "T">
+<!ENTITY editBookmarkOverlay.tagsEmptyText.label             "Separate tags with commas.">
 <!ENTITY editBookmarkOverlay.description.label               "Description:">
 <!ENTITY editBookmarkOverlay.description.accesskey           "D">
 <!ENTITY editBookmarkOverlay.keyword.label                   "Keyword:">