Tiny doesn't honour system settings variations

I'm having problems when I try to change system setting (for example tiny.custom_buttons or tiny.template_list), even if I clear site cache.

It seems to be frozen to first settings I set up when I just installed tiny plugin (not default settings! the first time it worked, then it stopped).

NOTE: if I look inside "modx_system_settings" I can see my new settings, but manager pages just ignore it...

Any idea? Anybody experienced similar problems?

Thanks