Rearrange task tracks in Gantt view?

I am not sure if my problem is the same as Gantt View Widget sorting in which case there is unfortunately no solution; but here goes:

I use Firefox, and I have gotten this state:

… and I would like to rearrange the horizontal task “tracks” like this:

I’ve been trying to drag tracks around in the UI, but that does not work.

Is it possible to rearrange tracks in Gantt view as I want them?