Thanks to you, sjb007 and keet, I learned enough to solve the problem. I installed KDE desktop. I had no idea what a desktop was in Ubuntu world. And, as you said, it improved all programs looking. SH3D looks again pretty and fancy enough to my eyes, and the open/save dialog is no more D.O.S.-like, but graphic and friendly.

The last time, I was just very tired.



See ya!