your comments will only be visible when the user scrolls back to the starting
cells that are next to the cells that have the comments in them, the only way
now to make your comments appear is to freeze the panes after one more cell
and adjust the size of the comment using "edit comment" so that it fits into
the size of that cell.

you can also adjust the size of the cells to fit for your comment's actual
size so that when he targets the cell none of the comment will be cut when
freeze panes is applied.