MS SQL Server Management Studio 2008 cannot save table change

I got this message:
Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created. You have either made changes to a table that can't be re-created or enabled the option Prevent saving changes that require the table to be re-cretead.

the solution is:
Tools > Options > Designers > Table and Database Designers
unselect 'Prevent saving changes that require the table to be re-created' check box