Hi,
as in subject.
This time I did not notice at first (music far away from focus) so I had to redo a section, now I know, so next time I will resort to copy/paste instead.
Illustration, using alt+arrow to move:
Yes, this is a consequence of the slurs having to be snapped to new positions according to the new notated durations of the notes.
Aha! So if the notes are entered with Force duration on, the slurs will stay.
However, copy+paste to any position will retain the slurs no matter what the new notated durations will be.