During SDL_CreateWindow, SDL uses the _NET_WM_WINDOW_TYPE X11 property to
report to the window manager the type of window it wants to create. This
might be set to various things if SDL_WINDOW_TOOLTIP or
SDL_WINDOW_POPUP_MENU, etc, were specified. For "normal" windows that
haven't set a specific type, this hint can be used to specify a custom
type. For example, a dock window might set this to
"_NET_WM_WINDOW_TYPE_DOCK".
A variable specifying the type of an X11 window.
During SDL_CreateWindow, SDL uses the _NET_WM_WINDOW_TYPE X11 property to report to the window manager the type of window it wants to create. This might be set to various things if SDL_WINDOW_TOOLTIP or SDL_WINDOW_POPUP_MENU, etc, were specified. For "normal" windows that haven't set a specific type, this hint can be used to specify a custom type. For example, a dock window might set this to "_NET_WM_WINDOW_TYPE_DOCK".
This hint should be set before creating a window.