It is probably because of iThemes Security and its settings. So yeah, just go to wp-config and change DISALLOW_FILE_EDIT to false.
define( 'DISALLOW_FILE_EDIT', false );
Or just switch it off here: Dashboard -> Security -> WordPress Tweaks -> Configure Settings
Uncheck: Disable File Editor
Open up your wp-config.php file, and search for
Change true to false:
To enable the theme editor, follow these steps:
- Go to Appearance, select one theme (any one you like) and activate it.
- In this activated theme, go to Appearance → Editor → select the theme to edit (on the top right, above Templates. There is a drop-down click on it and select your previous theme.)
- Now select config.php or demo config.php and remove the define ( ‘DISALLOW_FILE_EDIT, true); code.
- Now click on Update file.
- Now change the theme to your previous theme.
Now you can find your editor in the Appearance drop-down.