private void OnKeyReleased(object sender, KeyEventArgs e)
        {
            // If we press the backspace key when completionWindow is open, we
            // close the window.
            if ((e.Key == Key.Back || e.Key == Key.Space) && _completionWindow != null)
            {
                _completionWindow.Close();
                _completionWindow = null;

                return;
            }

            // If enter or tab is pressed when the completionWindow is open,
            // request insertion of the selected word.
            if ((e.Key == Key.Enter || e.Key == Key.Tab) && _completionWindow != null)
            {
                _completionWindow.CompletionList.RequestInsertion(e);

                return;
            }

            // Debugging
            if (_debuggerService.IsActiveDebugging)
            {
                switch (e.Key)
                {
                case Key.F10:
                    _debuggerService.StepOver();
                    break;

                case Key.F11:
                    _debuggerService.StepInto();
                    break;
                }
            }
        }