private void AddSoundtrackButton_Click(object sender, RoutedEventArgs e)
        {
            if (ProjectIsNotNull())
            {
                var result = openSoundtrackDialog.ShowDialog(this);
                if (result.GetValueOrDefault())
                {
                    if (File.Exists(openSoundtrackDialog.FileName))
                    {
                        var soundtrackPath = openSoundtrackDialog.FileName;

                        var soundtrack = new ClipSynthSoundtrack()
                        {
                            Path = soundtrackPath,
                            Offset = 0,
                            Checked = true,
                        };

                        RemoveSoundtrackButton_Click(null, null);
                        project.Soundtrack = soundtrack;
                        SoundtrackListBox_AddItem(soundtrack);

                        project.Dirty = true;
                    }
                }
            }
        }
        private void SoundtrackListBox_AddItem(ClipSynthSoundtrack soundtrack)
        {
            var item = new ListBoxItem();
            var checkBoxContent = new CheckBoxContent(soundtrack.Path, IOPath.GetFileName(soundtrack.Path), ListBoxCheckBox_Checked, String.Empty, soundtrack.Offset, 0, 0);
            checkBoxContent.UniqueIdLabel.Visibility = System.Windows.Visibility.Collapsed;
            checkBoxContent.Thumbnail.Visibility = System.Windows.Visibility.Collapsed;
            checkBoxContent.EndTextBox.Visibility = System.Windows.Visibility.Collapsed;
            checkBoxContent.Margin = new Thickness(0, 6, 0, 0);

            checkBoxContent.Tag = soundtrack;
            checkBoxContent.CheckBox.IsChecked = soundtrack.Checked;
            checkBoxContent.Label.ToolTip = soundtrack.Path;
            checkBoxContent.Label.Tag = soundtrack.Path;
            item.Content = checkBoxContent;
            checkBoxContent.StartTextBox.TextChanged += ListBoxTextBox_TextChanged;

            SoundtrackListBox.Items.Add(item);
        }