When multiple accounts are running on the same window, each one creates a copy of the settings of all accounts. Meaning that changing the settings of one account won't affect the copies existing on other tabs.
Since these settings are shared in the local storage (or cookies? I don't remember), it means that validating the settings on one account will rollback any setting changed on other tabs.

Currently, the other solution to edit settings for multiple accounts on the same window is start only one account, change the settings, log out then restart with the second account etc.