gdk:window-deiconify (window)

window -- a toplevel gdk:window object

Attempt to deiconify (unminimize) window. On X11 the window manager may choose to ignore the request to deiconify. When using GTK, use the gtk:window-deiconify function instead of the gdk:window variant. Or better yet, you probably want to use the gtk:window-present function, which raises the window, focuses it, unminimizes it, and puts it on the current desktop.