diff --git a/layout/forms/nsIListControlFrame.h b/layout/forms/nsIListControlFrame.h
index 0ee3fc3aa77..4e68753e4d2 100644
--- a/layout/forms/nsIListControlFrame.h
+++ b/layout/forms/nsIListControlFrame.h
@@ -38,6 +38,7 @@ class nsIContent;
 class nsIListControlFrame : public nsISupports {
 
 public:
+  NS_DEFINE_STATIC_IID_ACCESSOR(NS_ILISTCONTROLFRAME_IID)
 
   /**
    * Sets the ComboBoxFrame
@@ -51,12 +52,6 @@ public:
    */
   NS_IMETHOD GetSelectedItem(nsString & aStr) = 0;
 
-  /**
-   * Tells the list it is about to drop down
-   *
-   */
-  NS_IMETHOD AboutToDropDown() = 0;
-
   /**
    * Initiates mouse capture for the listbox
    *
diff --git a/layout/html/forms/public/nsIListControlFrame.h b/layout/html/forms/public/nsIListControlFrame.h
index 0ee3fc3aa77..4e68753e4d2 100644
--- a/layout/html/forms/public/nsIListControlFrame.h
+++ b/layout/html/forms/public/nsIListControlFrame.h
@@ -38,6 +38,7 @@ class nsIContent;
 class nsIListControlFrame : public nsISupports {
 
 public:
+  NS_DEFINE_STATIC_IID_ACCESSOR(NS_ILISTCONTROLFRAME_IID)
 
   /**
    * Sets the ComboBoxFrame
@@ -51,12 +52,6 @@ public:
    */
   NS_IMETHOD GetSelectedItem(nsString & aStr) = 0;
 
-  /**
-   * Tells the list it is about to drop down
-   *
-   */
-  NS_IMETHOD AboutToDropDown() = 0;
-
   /**
    * Initiates mouse capture for the listbox
    *