Drag Sexpr Backward/Forward Up/Down deletes immediately preceding/following line comments

[PEZ]

As was demonstrated in this screencast: https://youtu.be/d0K1oaFGvuQ?t=1287

Dragging a form backward up deletes the immediately preceding line comments.

I've tested around a bit and note that this goes for all up/down dragging.

Reproduction. Have the cursor in or adjacent to :backward-up in the following form.

:forward-down
;; forward down
(comment
  ;; backward-up
  :backward-up
  (def foo :foo)
  (def bar :bar)
  :forward-up
  ;; :forward-up
  )
;; backward down
:backward-down

Drag Sexpr Backward Up

Expected:

;; forward down
:backward-up
(comment
  ;; backward-up
  (def foo :foo)
  (def bar :bar)
  :forward-up
  ;; :forward-up
  )
;; backward down
:backward-down

Actual:

;; forward down
:backward-up
(comment
  (def foo :foo)
  (def bar :bar)
  :forward-up
  ;; :forward-up
  )
;; backward down
:backward-down

Dragging the form (def foo :foo)) backward up does not kill the ;; foo line comment.

We have the same bug when dragging all keywords as they are named in the repro text.