--- a/templates/fancy.html	Sun Feb 07 22:57:31 2016 +0800
+++ b/templates/fancy.html	Sun Feb 07 23:51:41 2016 +0800
@@ -51,7 +51,10 @@
       var chart = c3.generate({
         bindto: '#chart',
         size: {height: 500},
-        tooltip: {format: {title: function(x) { return data.titles[-x]; }}},
+        tooltip: {format: {title: function(x) {
+          var c = data.csetmap[-x];
+          return c.rev + ':' + c.shortnode + ' <span style="color: darkblue;">' + c.branch + '</span> ' + c.firstline;
+        }}},
         axis: {x: {tick: {format: function(x) { return -x; }}}},
         data: data
       });

--- a/viewer.py	Sun Feb 07 22:57:31 2016 +0800
+++ b/viewer.py	Sun Feb 07 23:51:41 2016 +0800
@@ -9,6 +9,7 @@
 from collections import OrderedDict
 from urllib import quote_plus
 
+from tornado.escape import xhtml_escape
 from tornado.ioloop import IOLoop
 from tornado.options import define, options
 from tornado.web import Application, RequestHandler, URLSpec
@@ -247,7 +248,7 @@
         marks, moremarks = self.getmarks()
         results, _ = self.getresults(changesets, marks=marks, colors=False)
         json = []
-        titles = {}
+        csetmap = {}
         for cset in changesets:
             item = {'rev': -cset['rev']}
             for mark in marks:
@@ -258,17 +259,18 @@
             extra = [cset['branch']] + cset['tags']
             if len(cset['parents']) > 1:
                 extra.append('(merge)')
-            titles[cset['rev']] = '{}:{}: {} {}'.format(
-                cset['rev'],
-                cset['node'][:12],
-                ' '.join(extra),
-                cset['desc'].partition('\n')[0])
+            csetmap[cset['rev']] = {
+                'rev': cset['rev'],
+                'branch': cset['branch'],
+                'shortnode': cset['node'][:12],
+                'firstline': xhtml_escape(cset['desc'].partition('\n')[0])
+            }
         data = {
             'names': marks,
             'x': 'rev',
             'json': json,
             'keys': {'x': 'rev', 'value': marks.keys()},
-            'titles': titles
+            'csetmap': csetmap
         }
         context = {
             'changesets': changesets,