Bug 451606

SUMMARY
In the "Tasks view", we can sort by "Due date" to have the soonest due task to be printed first. This works well, except when you have sub-tasks. Then, only the due date of the primary task is taken into account. I believe (this can be discussed of course) that this is not the expected behaviour: "due date" sorting is a way to prioritise tasks according to time left for the completion. In that regard, if a sub-task is due TODAY, even if the primary task is due later (or has no due date at all), I would expect the sub-task to appear in the TODAY category.

STEPS TO REPRODUCE
1. Generate a primary task without due date and attach a sub-task with a due date, for example today
2. In the task view, sort by due date

OBSERVED RESULT
Even if the sub-task is due today, it appears in the category in which the primary task belongs (No defined date).

EXPECTED RESULT
In order to see what I need to do e.g. today, I would expect the tasks to be sorted according to the earliest due date of the sub-tasks. This way, if a sub-task is due today, it would appear on top of the task view, for me to realise I have to tackle it, no matter the due date of the primary task.