HTML Form Tag isn't being generated when page is rendered in Firefox

I developed a basic web page in MVC 2 for learning the framework, and I am stuck in this situation:

I have 3 classes开发者_如何学编程: Client - Product - New. And for all need to display a modal popup to create/edit action. For display the modal i used JQuery and jqModal plug-in.

I created the controllers for all objects, the views for Index action, and Delete action. For the Create/Edit Action I created a partial view named ModalBox. Inside this partial view, I have an Ajax.BeginForm, and it calls another partial, that represent the form of the objects.

This works very fine, ... for the project object! in FireFox 3.6, for others object's the form tag is missing...

The question is: Why?

I solved the problem re-importing the master page, the old master page is a common master page, the new is a master page mvc.

The new master page doesn't have the tag form.

I based in this article:

http://geeks.ms/blogs/etomas/archive/2010/05/04/asp-net-mvc-formelement-is-null-o-como-un-peque-241-o-error-te-hace-perder-el-tiempo.aspx?CommentPosted=true#commentmessage