I only just became aware of this extra.
Far better than the other one.
I recommend checking it out in the package manager by searching "tinymcerte"
Or github here:
https://github.com/modxcms/tinymce-rte
Only problem is it doesn't seem to work with MIGX yet.
Try it now.
There was some bugfix in the last version of Jan 2016.
TinymceWrapper: Complete back/frontend content solution.
Harden your MODX site by
passwording your three main folders:
core, manager, connectors and renaming your
assets (thank me later!)
5 ways to sniff / hack your own sites; even with renamed/hidden folders, burst them all up, to see how secure you are not.