How to update Linq to SQL dbml database layout in Visual Studio 2012?

I have not been working with the Linq to SQL tool before and had to make some changes to an existing Visual Studio 2012 project. Some new colums were added to a database table and i needed to update the corresponding dbml file in the Visual Studio project.

How-i-fixed-it:
I found the solution here: http://stackoverflow.com/questions/1110171/how-to-update-linq-to-sql-dbml-file

Delete the modified tables from the designer, and drag them back onto the designer surface from the Database Explorer. I have found that, for this to work reliably, you have to:
a. Refresh the database schema in the Database Explorer (right-click, refresh)
b. Save the designer after deleting the tables
c. Save again after dragging the tables back.