--- src/toon_init.cshape	2001-06-24 18:28:17.000000000 +0200
+++ src/toon_init.c	2014-03-16 13:44:18.000000000 +0100
@@ -29,6 +29,8 @@
 Display *
 ToonOpenDisplay(char *display_name)
 {
+  int event_base, error_base;
+
   toon_display=XOpenDisplay(display_name);
   if (toon_display == NULL) {
     if (display_name == NULL && getenv("DISPLAY") == NULL)
@@ -39,6 +41,11 @@
 	      TOON_MESSAGE_LENGTH);
     return(NULL);
   }
+  if (!XShapeQueryExtension(toon_display, &event_base, &error_base)) {
+    strncpy(toon_error_message, _("Display doesn't support the SHAPE extension"),
+	    TOON_MESSAGE_LENGTH);
+    return(NULL);
+  }
   ToonInit(toon_display);
   return toon_display;
 }