In ‘Graphic Editing’ in the ‘Engraving Mode,’ I could select a handle of a tie and could drag it.
However, the position is restored when releasing the mouse button.
You’re not missing anything: at the moment, it appears that dragging the handles for the second segment of a tie where it crosses onto a new system doesn’t work as expected. I’ll make a note of this so the team can look into it when we get a chance.