Transaction got confirmed but it still shows the Unconfirmed one (Double Spend), when will this be removed from blockchain?
Just wait a few days (usually 3 or 4 days) and the transaction will end up getting dropped from the mempool just like it never existed.
It was removed after few hours I think.
first of all an RBF transaction is a kind of double spend, because you are practically creating a new transaction and it doesn't matter that you are spending the same output and sending to the same key.
secondly not all bitcoin nodes have implemented RBF or accept these transactions. some of them will reject it as a double spend and so they will keep the first one in their mempool until it becomes invalid.
thirdly i believe from what you said your first transaction was not an RBF transaction. the first one needs to be and RBF transaction so that you create a new one that easily replaces it with a higher fee. if you haven't then that means you are simply double spending and it doesn't matter if you only mark the second one as "replaceable".
Thank you very much pooya87, I learned new things about double spend, and the electrum did a perfect job.
I didn't know that we can "extend" the transaction to another one, after the first confirmation it got listed in blockchain.info