The problem still exists and nobody has responded yet. The sorting is useless if everything changes back after one other action. The gantt chart is not really a Gantt chart and instead of making PM easier, it just becomes a confusion process with tasks and deadlines all over the place.
Just created our Bitrix account for my small company. I agree whole-heartedly with the last several complaints. If I cannot create the order for my tasks to be displayed and have it remain so, this "very powerful" program is worth next to nothing for project management.