Shortcut for custom menu items

I know I can assign a shortcut to a menu item like:
ShortcutKeys = System.Windows.Forms.Keys.C | System.Windows.Forms.Keys.Shift
but this would lock the shortcut. how can I make it so it’s user-definable in the settings window??

Currently my menu item shows as not supporting shortcuts:

Subscribe to the GH_DocumentEditor.AggregateShortcutMenuItems event and append ToolStripMenuItems

        internal static List<ToolStripMenuItem> MenuEntryAllowShortcut = new List<ToolStripMenuItem>();

        internal static void RegisterEntriesForShortcut()
            GH_DocumentEditor.AggregateShortcutMenuItems += AggregateShortcutMenuItems;

        /// <summary>
        /// Register menu items with Grasshopper so that keyboard shortcuts can be assigned
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private static void AggregateShortcutMenuItems(object sender, GH_MenuShortcutEventArgs e)