XN4 and XN-Neo behaviour change in Gmail: Concerns about privacy and account handling

I want to ask about a behaviour lost in the new email checkers (XN4 and XN-Neo), what i think some people doesn't notice and maybe some could be concerned. Maybe is for the new Firefox limitations or Google changes, but maybe the developer can clarify things or do something (or maybe not).

In my case, i have mainly 4 Gmail Accounts, 3 normal Google accounts (Personal, for work, and another one shared with others people) and a Google Apps account (For work, separated from the another one). In the beginning, i have a lot of problems because i don't want to be logged in at the wrong account when i'm using internet in some ways, for example, sometimes i realized that i was in Youtube and i was logged in my work account, making the history playback in that account, because the mail checker i'm using at that time is at that moment in that account or it keeped the cookie and it wasn't logged out after the check. I fixed that then using various browser to use different group of accounts, normally 2 or 3, and some accounts were sending notifications emails when they had new emails automatically.

With the newers Firefox and XN3 i fixed that, because XN permanetly keep my personal account logged as default, and the other ones are opened in a background tab keeping the things not mixed and all in the same browser. That's perfect. Besides, i learn about the "delegated" accounts in gmail, making inside Gmail some accounts accesible through others ones in one way only, whats is cool.

But now, with all of these changes in Gmail, Firefox and XN4/NEO, seems it's more difficult to keep them separated. Looking that, you NEED to have logged in to all your accounts at the same time and in the same cookie enviroment to have access to them and use the mail checkers. i used XN4, XN-NEO and Gmail Notifier too, which is how those email checkers look for the different accounts, with the login cookies stored in the browser (i think) instead of log in to check every time separatedly or having the cookies separated. If you are using one of these email checkers and have multiple gmail accounts, on Gmail (or in the main Google page) if you click on your avatar on the right upper corner, you can see all the accounts you are logged at the time, and although is something based in the cookies and it's only affected by the working browser, this is making doubts about my privacy between accounts, Google is showing direct access and info for accounts i don't want to be visible directly from its webpages, and the delegated gmail thing is a bit more useless (in my main computer, completely useless with this) when all the other accounts are there (In the avatar in gmail is where you can change between delegated accounts too). All that thing still don't happens in X-Notifier 3, tested today, because seems it stills doing the work of logins and cookies separatedly.

Thats why, in my case, if it should be possible to keep the cookies in separated "containers" inside the browser, although you need to do in some way a manual login in the beginning, to keep the checking at least, it should be ok. My main thing is to keep everything separated, and that's why X-Notifier 4, X-Notifier NEO and Gmail Notifier aren't doing the job for me. It seems i'm going to return to have a lot of browsers. I don't know why are making so hard (Gmail, Firefox, etc.) to make access to your account(s) for see only if you have new email, only a number, without anything more fancy, that's all.