(gtk:clg-init) (gtk:within-main-loop (make-instance 'gtk:window ; :type :toplevel :title "Test" :border-width 5 :visible t :show-children t :child (make-instance 'gtk:button :label "Hello World!" :signal (list 'clicked #'(lambda () (write-line "Hello World!")))) :signal (list 'delete-event #'(lambda (event) (declare (ignore event)) (write-line "Destroying window") nil ; Returning NIL generates a destroy event ))))