Hi Michael, it works now. It was the mesh option at my MoIConvert.js script file that override the "persist" allways. Thank you. :)

For the options UI - in the past at Rhino 3 there was a render plugin called Rhinoman. It allow to render per render engines based on the Renderman standard. The Renderman standard allow to use dozen of options and so the coder Brian Perry added a simple list/table UI for seldom needed features. At this simple tables/lists the user could add options like needed - first column option name and second column value. I see now that you implement something like for the shortcut keys.
Why not add a button somewhere at the general options that open a window with a table that show the moi.ini? So, the user don't need to search it at the hard disk, get quick&easy access and you don't need to work on the UI for every little new options. The MoI interface is so nice sophisticated - this little addition could make it perfect for the advanced users too. For me it sounds like a must. ;) The UI wouldn't be complicated, only a little button needs be added. At the general options you could add a line "MoI ini file" with an "Edit" button. An advantage would be, that if the user has more than one ini file at his system (by an user fault), that the UI would only open the ini file that is known and used by MoI.

If you would add the table, than you could make that all options titles like [Mesh Export] could be show bold or with a empty line before.