In new firmware f7 reverses sample , so in new manual it still says
F7 sets the start to the previous slice’s end.
Which is lost now , has this changed to another f button as can’t find it any more,
From the new manual
F4: Shift slice left. In multi-mode, F7 sets the start to the previous slice’s end.
F5: Force selected point to zero crossing, long-press to force all points to zero crossing F6: Shift slice left. In multi-mode, F9 sets the end to the next slice’s start.
F7: Reverse Slice, long-press to undo. (see below for details)
F8: Set the loop time based on a number of repetitions.
So F7 doesn’t set to previous slice end it just reverses