Thread:Extension talk:OpenID Connect/Refresh Tokens/reply

Did you try setting

$PluggableAuth_Timeout = 0;

in LocalSettings.php to disable the inactivity logout? Or, you could set it to a higher value. It defaults to 30 minutes, if I recall correctly. Does that solve your problem? I will add to the documentation in PluggableAuth that a value of 0 disables the inactivity logout.