I had an incorrect fix for issue2550601. Changed schema to define class patches not patch. Changed commented out patches section in bug.item.html to use patches-1 an not patch-1 as a result of schema changes. The show open Milestones link had a leak of the @group value. If you clicked on show open tasks or show open bugs they group by priority. The url being formed for show open milestones was inheriting the @group if you were on an index page for bugs or milestones. Explicit set the @group to status (which a milestone does have) prevents the @group=priority from being applied to a milestone index page which results in a red error banner stating priority is an invalid param for milestones. ./demo.py -t devel now runs without obvious breakage.

@import url(style.css);

body { padding: 0;}
body > .header,
body > .footer
{
  margin: 0;
}
body .content { width: auto;}
.header h1 { font-size: 110%; }

table.classhelp th
{
  border-top: 1px solid #afafaf;
  border-bottom: 1px solid #afafaf;
  empty-cells: show;
  text-align: left;
  vertical-align: middle;
  white-space: nowrap;
}

table.classhelp td
{
  border-bottom: 1px solid #efefef;
  empty-cells: show;
  text-align: left;
  vertical-align: middle;
  white-space: nowrap;
}