Do you mean you have to double click it two times or just click twice period? Standard Windows shortcuts do require 2 clicks, you can put a shortcut in the Windows Quicklaunch toolbar to launch a program with a single click however.
I expect the first click is simply running Opus (the icon appears in the tool tray) and no listers are set to open on launch. Hence, the second double click is required to actually tell the running Opus process to open a lister.