Fluent.ComboBox.OnKeyTipPressed C# (CSharp) Method

        public virtual void OnKeyTipPressed()
        {
            this.Dispatcher.BeginInvoke(
                DispatcherPriority.Normal,
                (DispatcherOperationCallback)delegate(object arg)
                {
                    var ctrl = (ComboBox)arg;

                    // Edge case: Whole dropdown content is disabled
                    if (ctrl.IsKeyboardFocusWithin == false)
                    {
                        Keyboard.Focus(ctrl);
                    }
                    return null;
                },
                this);

            if (!this.IsEditable)
            {
                this.IsDropDownOpen = true;
            }
        }