There was a refreshing bug on Linux/jdk1.4 on SoundModulePanel.java which should be fixed now.
Also fixed GUIProperties.java to include getProperty("user.dir") in the path string, which makes Javasynth work inside JDistro - and probably helps on other environments too.
The fixes are included only in the CVS at the moment. Thanks to Desnoix Guillaume for these fixes.
The first release of Javasynth made today with version 0.5-alpha, which includes a working synth engine with around 20 different sound generating and modulating components, and a working Swing GUI.