If a notification is "about" more than one message -- then its "tap" action is to open the respective message list.
I'm talking about the notifications which AquaMail posts to the status bar.
It does not post any other (um, there is Android Wear too, but that's linked to status bar notifications), and certainly does not do anything "special" for this Floatify app.
Sounds like Floatify is another app which works by "spying on" other app's notifications. Not the best way to do it.
I'm attaching a text file with some technical bits on how to properly integrate with AquaMail, if the developer of this app is interested.