Thanks. yes I knew about the command but as an insider tester I put myself instead of majority of Windows 10 users that rely on the GUI.
I had hoped that at least a logout from Windows account would have locked the Bitlocker drive but then i found out Bitlocker is a system wide encryption, it doesn't care about the user account.
another feature I hope to see in the next version of Windows is the ability to lock a single folder.
for those kinds of flexibility i keep using VeraCrypt, at least until Microsoft adds those basic features.