transaction in ssis not expected

Hi,

       I have 4 execute sql tasks(E1,E2,E3,E4. all are connected) in my package.The package transaction option is 'supported' and E1's is 'required' and other 3 are supported.I intentionally made a syntax error in E2 and executed the package.But it is not rollbacking the data which is inserted in E1.What is the reason?If change the package transaction property to 'required',it will rollback. 

So, is it necessary to make the package transaction to 'Required' always?.Can we create multiple transactions in single packages(like E1(required) to E2 and E3(required) to E4) ?