DocType doesn't show on the desk

Im new to ERPNext and Frappe, this problem happens a lot, sometimes the doctypes i create doesn’t show on the app folder and sometimes they are there. Most recently i update one row of a doctype and then it vanish from the folder. In this case the docType ‘Part’ is missing.
I really dont know how to fix it and i already search for similar topics but i haven’t found any solution :frowning: