Asking to be remembered has nothing to do with the population of your login details; again, this behavior is controlled by your webbrowser.
"Remember Me" sets your cookie's "lifetime" to 0 (which in most browsers is forever, Edge differs), otherwise it should set the cookie lifetime to the setting in the control panel (you can see the switch in the do_login routine in /libs/html.inc.php)
There have been significant changes since your build, v7.6.0 is a major rewrite.
