ethereum.selectedAddress update is delayed.

[DeltaBalances]

Describe the bug
A minor bug, but ethereum.selectedAddress isn't immediately changed on the accountsChanged event, which is different behaviour from the previous version. Calling ethereum.selectedAddress from within the callback will return the old account.
A small timeout in javascript will show the change happening.

ethereum.selectedAddress is marked as deprecated in the docs, but it is still available for now.

No big issue because the accounts value is correct, but it might cause issues in a case where the callback calls a function that internally uses selectedAccount.

To Reproduce (REQUIRED)
MetaMask with 2 accounts connected.

Take the following javascript logging:

window.ethereum.on("accountsChanged", function (accounts) {
    if (accounts && accounts.length > 0) {
        console.log('log1: ' + accounts[0] + ' - ' + ethereum.selectedAddress);
        // wait for 1 millisecond to log again
        window.setTimeout(function() {
            console.log('log2: ' + accounts[0] + ' - ' + ethereum.selectedAddress);
        }, 1);
    }
})

log1 prints the accounts immediately after the event and log2 is identical with a small delay.

MetaMask 8.0.4

• on MetaMask login
  log1: account1 - null
log2: account1 - account1
• on change from account1 -> account2 in MetaMask
  log1: account2 - account1
log2: account2 - account2

MetaMask 7.7.9

• on MetaMask login
  log1: account1 - account1
log2: account1 - account1
• on change from account1 -> account2 in MetaMask
  log1: account2 - account2
log2: account2 - account2

Browser details (please complete the following information):

• OS: Windows 10
• Metamask 7.7.9 & MetaMask 8.0.4 on Firefox 78.0.2 & Brave 1.2.43.

[rekmarks]

@DeltaBalances thank you for bringing this to our attention. This will be fixed in MetaMask@8.0.6. We'll keep the issue open until then.