In practice multiple applications get confused, and some don't support -geometry or equivalent.
One specific case I dealt with was Chrome/Chromium that provided all sorts of annoyances until we dropped in a minimal WM (back then it was awesomewm, I didn't know about cage or it didn't exist yet)
In ye olden times, when most X11 applications understood "-geometry" and didn't try to do too much in absence of WM, things worked.
Chromium and possibly others (Chromium is just what I have personally dealt with) was confused about what did it mean to be fullscreen, and various other ideas regarding placing itself on screen.
I did success in making it work for a time, but it was problematic.
Comments
What's the point of the cage?
It's probably for building appliance/kiosk systems, though it's handy for anything where you just want to run a single application fullscreen.
If you want a single application fullscreen, you can just not start a window manager though.
In practice multiple applications get confused, and some don't support -geometry or equivalent.
One specific case I dealt with was Chrome/Chromium that provided all sorts of annoyances until we dropped in a minimal WM (back then it was awesomewm, I didn't know about cage or it didn't exist yet)
Haven't had that yet. I thought of a single application the whole time, aka. kiosk, then it shouldn't matter.
In ye olden times, when most X11 applications understood "-geometry" and didn't try to do too much in absence of WM, things worked.
Chromium and possibly others (Chromium is just what I have personally dealt with) was confused about what did it mean to be fullscreen, and various other ideas regarding placing itself on screen.
I did success in making it work for a time, but it was problematic.