How to add floating window in apps by using android service ‘system alert window’ like Facebook message chat heads
Might be possible with an extension for notifier i saw whilst browsing the current Extensions. I cant remember the name of it off the bat. Something like Cool Notifier, Its a paid extension but has a sort of floating window look to them. Ill have a hunt for it later and post here when found. Not sure if its what you need but might offer some of the function your looking for.
EDIT: Have a look at this, AwesomeDialogs Extension
If i see any more which might be of relevance i will add the links.