I want to change the timesheet grid so the lines are sorted in alphabetical order according to the project name.

I already tried to order the records by adding this :

_order = 'project_id asc'

But it gives a weird sorting where the lines which have a timesheet on monday are sorted correctly, and THEN the lines which have a timesheet on tuesday BUT NOT ON MONDAY are sorted correctly, and then the lines which have a timesheet on wednesday BUT NOT ON MONDAY OR TUESDAY, etc.

I would like to get a global sort of all the lines, without being dependent of the timesheet entries.

Edit : Here's a picture of what kind of sorting I get : https://ibb.co/JFzCRTZ

(Project names are confidential, but each "group of lines" you can identify on the picture is ordered in alphabetical order)