Hi Henrik,
Just grabbed a git clone of your branch since I can’t hold myself back 
Looks really good and works really well (apart from the outstanding issues that you mentioned above). I wish I could help with these things, but I’m no programmer I’m afraid!
One thing I thought might be a worthy addition - when dragging an existing task which has a due date onto another task to make it a successor, it would be great if the parent task inherit the child’s due date if it is sooner than what the parent has. Does that make sense?
I did also manage to break something - by repeatedly dragging and dropping a task onto another (it never seemed to update in between in this case, not sure if that’s because I was pending a page refresh, or if I just did it too quickly), I managed to break one of my projects so that I can’t view the page any more! Digging into the database, I saw duplicate entries in the dependencies table, which looked like this:
mysql> select * from dependencies;
+——+———————+————————+—————————-+
| id | successor_id | predecessor_id | relationship_type |
+——+———————+————————+—————————-+
| 2 | 1221 | 1224 | NULL |
| 3 | 1222 | 1088 | NULL |
| 6 | 1136 | 1223 | NULL |
| 7 | 1223 | 1136 | NULL |
| 8 | 1223 | 1136 | NULL |
| 9 | 1223 | 1136 | NULL |
| 10 | 1223 | 1136 | NULL |
+——+———————+————————+—————————-+
7 rows in set (0.00 sec)
After deleting the duplicates, the page could render again:
mysql> delete from dependencies where successor_id=1223;
Query OK, 4 rows affected (0.00 sec)
Just from my short time with this update, I can see it dramatically moving my use of tracks from a personal task management tool to something that can easily be used both for that and for simple project management (and I mean “project management” in the business sense, rather than the GTD sense!). Tie it in with the ability to assign tasks to other users (I’ve seen a few posts/mails about that), and Tracks will soon be taking on MS Project and its ilk 
