After installing version 3.0 of WordPress, Thesis theme has a minor conflict. When trying to access the Custom File Editor from the admin toolbar, you may see a message similar to this:
Fatal error: Call to undefined function use_codepress() in
/ANY_OLD_DIRECTORY/public_html/wp-content/themes/thesis_XX/lib/admin/admin.php on line XX
The editor is still usable but will no longer have syntax highlighting until DIYThemes finds a solution. until then, this fix allows you to again access the file when in WP admin.
You will need to access your site via FTP; dowload admin.php from this directory path. (wp-content/themes/
Using a plain text editor, comment out the line that calls for syntax highlighting; place two forward slashes just before it:
// if (use_codepress()) add_action('admin_print_footer_scripts', 'codepress_footer_js');
Save and send the revised file to the server to replace the current file. Should work again now!
Modifying this file will require using both a plain text editor and FTP. Many web hosts offer free FTP clients in their Control Panel or do a search based on your Operating System and find a free one online.
This fix will work until there is a more permanent one from the folks at Thesis.