I want to add new Column to table. But while saving, It showing this warning message and not allowed to save. 
 "Saving changes is not permitted. the changes you have made requires 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-created." 

SOLUTION: 
Go to tools menu in SQL Server Go to the menu Tools - Options - Designers and uncheck Prevent Saving changes that require table re-creation.
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