When I make a pygame window (I believe it uses SDL), it launches as a popup window, as I want, since then it doesn't affect the layout or visibility of elements. But if I launch a simple program using GTK and Cairo, it doesn't launch as a popup. Is there some specific env flag, signal, etc. that needs to be used to launch a window as a popup rather than a tiled window?
pygame hello world code
cairo+gtk code, GTK Window section, past mid point of page
To do this in GTK, you need to call
i3 will take window hints, and if a window tells i3 it is a dialog window, it will make it float automatically.