Dialog windows should be set transient for the main application
window they were spawned from. This allows
[window managers][gtk-X11-arch] to e.g. keep the
dialog on top of the main window, or center the dialog over the
main window. Dialog.newWithButtons and other convenience
functions in GTK+ will sometimes call
Window.setTransientFor on your behalf.
Passing NULL for parent unsets the current transient window.
Dialog windows should be set transient for the main application window they were spawned from. This allows [window managers][gtk-X11-arch] to e.g. keep the dialog on top of the main window, or center the dialog over the main window. Dialog.newWithButtons and other convenience functions in GTK+ will sometimes call Window.setTransientFor on your behalf.
Passing NULL for parent unsets the current transient window.
On Wayland, this function can also be used to attach a new GTK_WINDOW_POPUP to a GTK_WINDOW_TOPLEVEL parent already mapped on screen so that the GTK_WINDOW_POPUP will be created as a subsurface-based window GDK_WINDOW_SUBSURFACE which can be positioned at will relatively to the GTK_WINDOW_TOPLEVEL surface.
On Windows, this function puts the child window on top of the parent, much as the window manager would have done on X.