To hansmex: The double click calls the same command and causes the exact same behaviour.

I have also tried to reinstall SH3D by clicking on the banner "Lauch SH3D with Java Web Start" on page http://www.sweethome3d.eu/download.jsp but it only brings me the Java official download page.

By the way, the version of javaws installed on my computer is "Java(TM) Web Start 1.6.0_17"