[6.1/trunk][regression] impossible to create a custom model field anymore using the user interface

[Raphaël Valyi - http://www.akretion.com]

See the attached screenshot,

here I tried to add a field called "x_closed_deal_rate" of type float on the product.pricelist model but it won't save with an error on the top right side corner: "the following are invalid: Model"

See screenshot. Hope this helps.