Click Sort at the top of the list of Comments to pop up a window that makes it easy to order your Comments.
Once you’ve got the window open, drag to reorder then click Update Order to save your changes.
You can also sort Groups within a Library – assuming you authored the Group.
To move Comments you have authored, flip each Comment’s Not Selected toggle to Selected.
This toggle is in the top-right of each Comment’s row (#1 and #2). Then click Move in the Comments menu (next to Sort). You can move more than one Comment at a time assuming they share the same destination.
In the resulting popup choose a destination Library (#3) and destination Group within that Library (#4). You can choose whether to edit the destination for your Comment(s) or continue editing the current Library.
Click Move ‘Em! to complete the move.
Comments can only exist in one Group/Library combination.