diff --git a/src/ecmascript/spidermonkey/document.c b/src/ecmascript/spidermonkey/document.c
index 5bc24a6b..32b80cb2 100644
--- a/src/ecmascript/spidermonkey/document.c
+++ b/src/ecmascript/spidermonkey/document.c
@@ -49,6 +49,7 @@
 static JSBool document_get_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 static JSBool document_set_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 
+/* Each @document_class object must have a @window_class parent.  */
 const JSClass document_class = {
 	"document",
 	JSCLASS_HAS_PRIVATE,
diff --git a/src/ecmascript/spidermonkey/form.c b/src/ecmascript/spidermonkey/form.c
index 5f243f8a..78fefffc 100644
--- a/src/ecmascript/spidermonkey/form.c
+++ b/src/ecmascript/spidermonkey/form.c
@@ -52,6 +52,7 @@
 static JSBool input_get_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 static JSBool input_set_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 
+/* Each @input_class object must have a @form_class parent.  */
 static const JSClass input_class = {
 	"input", /* here, we unleash ourselves */
 	JSCLASS_HAS_PRIVATE,	/* struct form_state * */
@@ -579,6 +580,7 @@ form_elements_namedItem(JSContext *ctx, JSObject *obj, uintN argc, jsval *argv,
 static JSBool form_get_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 static JSBool form_set_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 
+/* Each @form_class object must have a @document_class parent.  */
 static const JSClass form_class = {
 	"form",
 	JSCLASS_HAS_PRIVATE,	/* struct form_view * */
@@ -845,6 +847,7 @@ get_form_object(JSContext *ctx, JSObject *jsdoc, struct form_view *fv)
 
 static JSBool forms_get_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 
+/* Each @forms_class object must have a @document_class parent.  */
 const JSClass forms_class = {
 	"forms",
 	JSCLASS_HAS_PRIVATE,
diff --git a/src/ecmascript/spidermonkey/location.c b/src/ecmascript/spidermonkey/location.c
index 8546934b..39728bb5 100644
--- a/src/ecmascript/spidermonkey/location.c
+++ b/src/ecmascript/spidermonkey/location.c
@@ -126,6 +126,7 @@ history_go(JSContext *ctx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
 static JSBool location_get_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 static JSBool location_set_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 
+/* Each @location_class object must have a @window_class parent.  */
 const JSClass location_class = {
 	"location",
 	JSCLASS_HAS_PRIVATE,
diff --git a/src/ecmascript/spidermonkey/unibar.c b/src/ecmascript/spidermonkey/unibar.c
index 39620dbd..a0108d1c 100644
--- a/src/ecmascript/spidermonkey/unibar.c
+++ b/src/ecmascript/spidermonkey/unibar.c
@@ -47,6 +47,7 @@
 static JSBool unibar_get_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 static JSBool unibar_set_property(JSContext *ctx, JSObject *obj, jsval id, jsval *vp);
 
+/* Each @menubar_class object must have a @window_class parent.  */
 const JSClass menubar_class = {
 	"menubar",
 	JSCLASS_HAS_PRIVATE,	/* const char * "t" */
@@ -54,6 +55,7 @@ const JSClass menubar_class = {
 	unibar_get_property, unibar_set_property,
 	JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub
 };
+/* Each @statusbar_class object must have a @window_class parent.  */
 const JSClass statusbar_class = {
 	"statusbar",
 	JSCLASS_HAS_PRIVATE,	/* const char * "s" */