public PackageToolbar() { ResolveDependencies(); m_MainContainer = new VisualElement { name = "toolbarMainContainer" }; Add(m_MainContainer); var leftItems = new VisualElement(); leftItems.AddToClassList("leftItems"); m_MainContainer.Add(leftItems); extensions = new VisualElement { name = "extensionItems" }; leftItems.Add(extensions); m_BuiltInActions = new VisualElement { name = "builtInActions" }; m_BuiltInActions.AddToClassList("rightItems"); m_MainContainer.Add(m_BuiltInActions); m_ProgressContainer = new VisualElement { name = "toolbarProgressContainer" }; Add(m_ProgressContainer); m_DownloadProgress = new ProgressBar { name = "downloadProgress" }; m_ProgressContainer.Add(m_DownloadProgress); m_ErrorContainer = new PackageToolBarError(m_PackageDatabase) { name = "toolbarErrorContainer" }; Add(m_ErrorContainer); InitializeButtons(); }