I try new firefox 4 with last fckeditor version and all header tags, except title, are removed. Is it a bug in in fckeditor or in firefox? I think it's a firefox problem, what do you think?
I'm seeing this same problem with the final Firefox 4 release. I narrowed it down to the presence of META tags in the head block. If you edit a page with META tags in the head block, FCKeditor deletes everything in the head block except for the title tag. If you don't have any META tags in the head block, everything is left alone. I have confirmed that this problem does not occur in the latest release of CKeditor, so it is apparently something specific to FCKeditor and Firefox 4. The same exact version of FCKeditor works fine in Firefox 3.x, so it would appear to be some special interaction between FCKeditor and Firefox 4 that is causing the problem.
Re: Header tags in firefox 4 beta