To be displayed correctly on odoo app (In a given category and not only in all or hidden)
the module category in the __openerp__.py file should be one of these:

    "Accounting",
    "Discuss",
    "Document Management",
    "eCommerce",
    "Human Resources",
    "Industries",
    "Localization",
    "Manufacturing",
    "Marketing",
    "Point of Sale",
    "Productivity",
    "Project",
    "Purchases",
    "Sales",
    "Warehouse",
    "Website",
    "Extra Tools",

'Accounting & Finance' will not work, as 'Project Management', ...