I don't get any javascript errors for the spellchecker here on threadsdev either on showthreaded or showflat and from what I can see in the code it looks OK. I'm using Mozilla 1.2 on Linux. But that shouldn't matter.
Possibly "document.replier.Body.value" could be changed to "document.forms['replier'].Body.value" but that shouldn't be necessary.
Edit: The storeCaret() functions is still missing here on threadsdev though, at least on showthreaded.
Donate to UBBDev today to help aid in Operational, Server and Script Maintenance, and Development costs.
Please also see our parent organization VNC Web Services if you're in the need of a new UBB.threads Install or Upgrade, Site/Server Migrations, or Security and Coding Services.