I had RadEditor working till some time ago the client reported that some features don't work anymore and they get the message "The command <command name> is not implemented yet” .
I’ve tried the same sequence on the SharePoint server browser (IE7) and it works fine. I’ve tested on other servers browsers (even with different version, IE8) and it worked fine with all features.
I made tests with other hosts with different OS version and browser version (even with different browsers) and the result is the same, some features don’t work.
Luís Nuno Silva