Hi folks.
If you triple click to select all gometries, the edges of the top and the bottom will also be smoothed which migth not be the final effect that is wanted.
A quick way of selecting only the vertical edges to be softened is as follow:
1 - Use a view that shows the object mostly from its side (a front, back, left or right view is even better.
2 - Do a right to left window select and avoid selecting any of the top and bottom edges.
Another one:
1 - Triple click to select all edges and faces (the softening engine will ignore the faces then, do not worry).
2 - Double click on the top while pressing the SHIFT key to Add/Subtract from the selection. The top will be deselected with its edges.
3 - Repeat step 2 for the bottom.
Just ideas.