What do you mean by full screen? The fullscreen mode hides the header at the top of the Gladys screen, isn’t that the case?
It’s not compatible with Gladys at the moment, there’s a feature request but few requests so far:
You’re mixing everything up @cce66 
The only solution here is simply to integrate the siren into Gladys, it’s not a very big job, someone just needs to do it 
No, that won’t meet the need; the solution here is simply to integrate the siren into Gladys.
Any contribution in that direction is welcome