how to start draftsight under linux after the menu item is missing

Hi,

I installed draftsight under unbutun 10.04. There was a menu item under Graphics. I could start DraftSight there. But now the menu item is dispeared. How could I start now. When I double click on a DWG file, DraftSight will pop up.

I know it is installed under /opt/ folder. Where is the exe file to start?

Thanks in advance

Cean