Electrum gap limit question

[Tungsten]

As I understand if gap limit is 20 and address with zero-based index #15 is used  - electrum will allocate 16 more addresses?
If address #15 will become empty again (funds from it sent out elsewhere making it's balance zero) - will it be returned to "gap pool" ?

[ThomasV]

no, it won't.
what matters is if the address has been used.