Current behavior:

If you press CTRL+z in a segment and the previous segment had been edited as well, the editor continues undoing the changes of the previous segment in the currently open segment, if all changes of the current segment are already undone

Expected behavior:

Editing history should be cleared when opening next segment and If you press CTRL+z in a segment and the previous segment had been edited as well, the editor should stop undoing when reached segment original state.