Allow "splitting up" a long task when a smaller one is dropped on it

There are times where I have a task scheduled for a large chunk of time. Then, there are things that interrupt that task and I’d like to just drag another task from the list into the slot where the other task overruled and TimeFinder “split” the larger task schedule automatically.

As I mention in the comment in the screenshots, it would be nice for a task that has “split” another task to “eat up” the other task as it’s dragged down versus trying to push the other task down. It might even be nice to support this through maybe long-press on the expanding lines and then dragging.

Also, having an “undo” button for fixing any mistakes would be nice.