I have seen your project, beautiful as always.
I'd like to let you know what I've discovered and maybe if you make corrections, explain to me what was wrong.
In the delete buttons you have chosen not to ask for confirmation to delete the record. Instead, I set each delete button to ask for confirmation.
Here is how the program behaves at this point:
1) if you create a task in the first tablegrid, select the record and then exit the tablegrid with the mouse, the record moves to the second tablegrid. If you then select the record, passed into the second tablegrid and exit the second tablegrid with the mouse, the record returns to the first.
2) if you create a record in the second tablegrid it is saved in the fourth. Not always but most of the time.
3) if you delete a record from any of the first 3 tablegrids and when asked to confirm the deletion you say no, the record moves to the fourth tablegrid