>> !        (let* ((cur-ovs (overlays-in (point) (1+ (point))))
>> !               (thumb-ov (car (cl-remove-if-not
>> !                               (lambda (ov) (overlay-get ov 'thumb-file))
>> !                               cur-ovs))))
>> !          (if thumb-ov
>> !              (delete-overlay thumb-ov)

BTW, now that I actually look at the code, I twonder why it doesn't use
remove-overlays.


        Stefan