Comment 16 for bug 144406

> BTW, Scilab 5.2.1 seems to work fine, though it's build around Java graphics as well.

 I take it back! On a different machine I had similar issues when running Scilab 5.2.1 (64-bit Linux version) demos presenting Xcos and Modelica (Scilab's counterpart of Simulink in Matlab).

I opened main window (Console), then clicked ? > Scilab Demonstration. A new window popped out and then went Xcos > Modelica demos > Ball on platform (but can be any other demo from that category). It opened Xcos window with a Simulink style diagram. Then, in Xcos window, I've clicked Simulation > Start. Scilab compiled the model and when the information about successful compilation was prompted Xcos window with models diagram disappeared from the GNOME panel. Also window with demos menu disappeared. They were available through Alt+Tab or Turbo+Tab. Minimizing windows returned them to the panel.

Scilab 5 is available on licence considered free, so, contrary to Matlab, source code should be available.
http://www.scilab.org/

Ubuntu 9.10 (Karmic) 64-bit with all the current updates
NVIDIA graphic card with property drivers enabled
Compiz enabled
$ uname -a
Linux ubuntu-user 2.6.31-20-generic #58-Ubuntu SMP Fri Mar 12 04:38:19 UTC 2010 x86_64 GNU/Linux
$ java -version
java version "1.6.0_0"
OpenJDK Runtime Environment (IcedTea6 1.6.1) (6b16-1.6.1-3ubuntu1)
OpenJDK 64-Bit Server VM (build 14.0-b16, mixed mode)

Hope it will be helpful.
 Piotr