Yes Marc - it is really nice to see 
in tinymce toolbar here in moodle.org and I am glad to say that GEONExT-plugin with JSXGraph filter is now finally stable but I am a little distrustful of getting any SEE plugins to moodle.org forums in the near future...
JSXGraph filter works with all themes and I fixed today the last known bug in it. If javascript is disabled people see an empty box, otherwise filter changes jsxgraph strings to dynamic graphs that can be re-edited with tinymce plugin called geonext which is using GEONExT applet to render proper JSXGraph strings. In editor content area graph strings are replaced with image placeholders because scripts tags can't be used inside editor content area. Plugin supports the same languages as GEONExT applet does and translation in moodle is using the same method as Dragmath plugin.
Old gxt files can be opened directly in applet from your desktop - even if filter itself does not support gxt as file format - and saved with plugin like any graph that you create yourself. Attached an example.
When filter supports only strings and hashed strings support only graph commands it means that students can safely use these graphs but they can't use freely javascript commands.
Plugin packages on my test server are still using the old files but I try to upgrade all my packages during this week and send you some more info in a new post once the new package versions are ready.
