Do you create WordPress themes for clients? Or just want a customised WordPress admin area in the back-end? You might also be looking for customisation to make it a better experience for your registered members to access the back-end to update their profiles or add some posts. Whatever your reason, WordPress allows you to easily tweak the admin dashboard.
Do you want to remove the theme editor from your WordPress blog/website? There can be various scenarios when the theme editor is not required at all in the WordPress dashboard. For instance, you are creating a website for your client who does not need to make any changes to the theme. You might have multiple administrators for your website, but you do not want them to have access to the theme edit panel. Then there is the risk of an accidental change to the theme.