-No because you filed B-2 extension before the B-2 I-94 expires.
If I withdaw my F application do I have to wait untill receving a "Withdrawed" notice before I can file another F application?
-Unless the B-2 extension is approved, no difference. If your B-2 extension is approved, and then F-1 is denied, you can file another F-1 using the new B-2 I-94.
If I file a second F application before my first F application is actually withdrawed by USCIS, it is possible for USCIS to see two same I-539s there.
-It does not matter.
Will this leads to another "Violating rule"
-No if the B-2 is approved.
Please help!