When I drop part of a timeitem at a holiday, I would like the timeitem to split (half before the holiday and half after the holiday) and join the two timeitems with an arrow. Can I just destroy the timeitem object and redraw it? Or is there a better way to achieve this?
There is no auto-split as you describe it. If it was me doing this I would probably do a Userdrawn time item that was drawn as two boxes with the line between them (hence I would not need to split it, just check where the holidays start and stop).
If you want to split it you can simply delete it and create two new ones; or one new and change the first…