FYI (I've submitted a feature request for this)
I have two tasks, A and B. A must be done before B. I mark A as a predecessor of B. But, a change request happened which is forcing me to move B to start a full month later. Moving B's start and end date forces the deletion of the predecessor indicator.
Even though there is now a large amount of lag between the two tasks, task A is still a predecessor of B and I want to keep that noted. I also do not want to have to guess on the amount of lag time to include when setting up a predecessor. Smartsheet should automatically just let me move task B without deleting the Predecessor relationship.