When FCKeditor is installed, the site administrator must visit and save the FCKeditor Global Profile for the excl_regex variable to be set. Unless the site administrator performs this action, the excl variable is rendered useless as it has no effect.
This is problematic in several cases, 2 of which I will specify:
1. The site administrator can set up everything correctly according to all instructions and warning messages, but the excl field will not be effective the site administrator specifically visits the FCKeditor Global Profile and saves it.
2. When FCKeditor is installed via an installation profile, the feckeditor_install function does not set the excl_regex variable, so the installation profile must include the fckeditor.admin.inc file and call the fckeditor_rebuild_selectors function for the FCKeditor Global Profile to set the excl_regex variable.
I propose that the fckeditor_rebuild_selectors function be split into two functions. An fckeditor_excl_regex function could be placed in the fckeditor.lib.inc file that took as a parameter, a specific profiles excl string and return the regex expression for this string. The fckeditor_rebuild_selectors function could then call the fckeditor_excl_regex function. This would allow the fckeditor_install function to also utilize the fckeditor_excl_regex function.
Sorry if any of this is not clear.