Installer with HTTP authorization does not allow login retry

When using an online installer for which the repository requires HTTP basic authentication the installation flow is as follows:

• Welcome screen, click "Next"
• "Fetching latest update infomation..." appears.
• Popup "Server Requires Authentication" appears.
• Enter username and password, click "Ok".
• Red message "Cannot retreive remote tree ." appears, "Next" button is greyed out.

There is no way to retry with a different username or password if the login details were entered incorrectly, other than completely restarting the installer.

If the login details were entered correctly there is no obvious way to continue the install at this point.

The install can however be completed by clicking "Settings" and performing one of the following two actions:

1. Changing the proxy from "System proxy settings" to anything else (and back again if necessary).
2. On the repositories tab, disabling the repository, clicking ok, reopening the settings and reenabling the repository.

At this point the "Next" button is now no longer greyed out and installation can continue.

See the attached video.