Index: main/panel.lisp
===================================================================
--- main/panel.lisp	(revision main,33)
+++ main/panel.lisp	(revision main,41)
@@ -56,5 +56,5 @@
   (let ((panel-ptr (new-panel (window-pointer window))))
     (when (null-pointer-p panel-ptr)
-      (signal 'panel-construction-error))
+      (error 'panel-construction-error))
     (make-instance 'panel :panel-ptr panel-ptr :client-window window)))
 
@@ -73,5 +73,5 @@
   (with-slots (panel-ptr) panel
     (unless (= (del-panel panel-ptr) +ok+)
-      (signal 'panel-destruction-error))))
+      (error 'panel-destruction-error))))