Simple double-click at the top of the window for it to resize to the maxumum screen. Standard Mac functionality - even Outlook does this now!
Thanks for the feedback!
I just tried this in my safari window, and it did nothing, so not sure it is completely standard.
We have a custom window for Agenda with no title bar. It gives the app a clean uncluttered look. It would be more tricky to add this feature there, with no bar to click. We’ll keep it in mind.