I can't tell if the prior issues (see below) related to gantt chart issue sorting are about new- or old-style gantt charts. I do know that the default 1.1.0 isn't very useful, since they're sorted by root_id (ie. parent issue id). That has little relation to the order that the issues need to be worked on in. I made a one-line change that worked for me: TODO: top level issues should be sorted by start date def gantt_issue_compare(x, y, issues) [(x.root.start_date or x.start_date or Date.new()), (x.start_date or Date.new()), x.root_id, x.lft] [(y.root.start_date or y.start_date or Date.new()), (y.start_date or Date.new()), y.root_id, y.lft] #if x.root_id == y.root_id # x.lft y.lft #else # #x.root_id y.root_id #end end I'm not 100% certain if it works in all cases, but for my DB (multi-project, multi-version, single nesting level issues), it works fine.
Full article: http://www.redmine.org/issues/7335#note-23