set_modal
Description:
Sets a window modal or non-modal.
Modal windows prevent interaction with other windows in the same application. To keep modal dialogs on top of main application windows, use [ method@Gtk.Window.set_transient_for] to make the dialog transient for the parent; most window managers will then disallow lowering the dialog below the parent.
Parameters:
| this |
a `GtkWindow` |
| modal |
whether the window is modal |