[dotnet-sdk-10.0.100-preview.6.25306.101] WPF Apps failed to open the TaskDialog window due to System.ArgumentException: Value does not fall within the expected range

[Junjun-zhao]

Description

When running against the 3rd party applications with dotnet-sdk-10.0.100-preview.6.25306.101, some WPF applications open TaskDialog window failed with below error message:
System.ArgumentException: Value does not fall within the expected range.

Reproduction Steps

Minimal Repro steps (Demo attached：TaskDialogDemo.zip):

The machine has 10.0.100-preview.6.25306.101 installed.

1. Create a default 9.0 WPF project.
2. Install Ookii.Dialogs.Wpf nuget package for the project.
3. Add below code in MainWindow.xaml.cs file (Please keep only these 2 namespaces):

   using Ookii.Dialogs.Wpf;
   using System.Windows;
   
   namespace ConfirmDialogDemo
   {
       /// <summary>
       /// Interaction logic for MainWindow.xaml
       /// </summary>
       public partial class MainWindow : Window
       {
           public MainWindow()
           {
               InitializeComponent();
   
               var dialog = new TaskDialog
               {
                   Content = "message"
               };
               var yesButton = new TaskDialogButton("Yes");
               dialog.Buttons.Add(yesButton);
               var result = dialog.ShowDialog();
           }
       }
   }
   

4. Build the project.
5. Update the runtime.config to let the project run against with dotnet-sdk-10.0.100-preview.6.25306.101:

   {
      "runtimeOptions": {
        "tfm": "net9.0",
        "frameworks": [
          {
            "name": "Microsoft.NETCore.App",
            "version": "10.0.0-preview.6.25306.101"
          },
          {
            "name": "Microsoft.WindowsDesktop.App",
            "version": "10.0.0-preview.6.25306.101"
          }
        ],
        "configProperties": {
          "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization": false,
          "CSWINRT_USE_WINDOWS_UI_XAML_PROJECTIONS": false
        }
      }
    }
   

6. Press F5 to run the application.

Expected behavior

App launch successfully with a pop-up dialog shows before the main window load.

Actual behavior

App launch failed with System.ArgumentException: 'Value does not fall within the expected range.'

Stack Trace:

   at Ookii.Dialogs.Wpf.NativeMethods.TaskDialogIndirect(TASKDIALOGCONFIG& pTaskConfig, Int32& pnButton, Int32& pnRadioButton, Boolean& pfVerificationFlagChecked)
   at Ookii.Dialogs.Wpf.TaskDialog.ShowDialog(IntPtr owner)
   at Ookii.Dialogs.Wpf.TaskDialog.ShowDialog(Window owner)
   at Ookii.Dialogs.Wpf.TaskDialog.ShowDialog()
   at ConfirmDialogDemo.MainWindow..ctor() in F:\Demos\ConfirmDialogDemo\ConfirmDialogDemo\MainWindow.xaml.cs:line 24
   at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean wrapExceptions)

Regression?

Yes

Verify Scenarios:

1. Windows 10 22H2 + dotnet-sdk-9.0.300: Pass
2. Windows 10 22H2 + dotnet-sdk-10.0.100-preview.5.25277.114: Pass
3. Windows 10 22H2 + dotnet-sdk-10.0.100-preview.6.25306.101: Fail

Known Workarounds

No response

Impact

Application crashes when the taskdialog window pop-up.

Configuration

Application Name: NuGetPackageExplorer, RMMVCookTool, AMDownloader, Autodesk Revit 2025
OS: Windows 10 22H2
CPU: X64
.NET Build Number: 10.0.100-preview.6.25306.101
App & App Source Location checking at:
https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2499151

Github Link：
https://github.com/NuGetPackageExplorer/NuGetPackageExplorer
https://github.com/acemod13/RMMVCookTool
https://github.com/antikmozib/AM-Downloader

Other information

App Repro steps：

The machine has dotnet-sdk-10.0.100-preview.6.25306.101 installed.

1. Copy AM-Downloader app from SourceShare\ConfirmDialogIssueApps\Apps to local machine.
2. Update the runtime.config to let the project run against with dotnet-sdk-10.0.100-preview.6.25306.101:

      {
             "runtimeOptions": {
               "tfm": "net8.0",
               "frameworks": [
                 {
                   "name": "Microsoft.NETCore.App",
                   "version": "10.0.0-preview.6.25306.101"
                 },
                 {
                   "name": "Microsoft.WindowsDesktop.App",
                   "version": "10.0.0-preview.6.25306.101"
                 }
               ],
               "configProperties": {
                 "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization": true,
                 "CSWINRT_USE_WINDOWS_UI_XAML_PROJECTIONS": false
               }
             }
     }
   

3. Launch AM Downloader.exe.
4. Click Help -> About menu.

Expected Result:
The About pop-up window will appear.

Actual Result:
The application crashes and get below error from Event View:

Application: AM Downloader.exe
CoreCLR Version: 10.0.25.30701
.NET Version: 10.0.0-preview.6.25306.101
Description: The process was terminated due to an unhandled exception.
Exception Info: System.ArgumentException: Value does not fall within the expected range.
   at Ookii.Dialogs.Wpf.NativeMethods.TaskDialogIndirect(TASKDIALOGCONFIG& pTaskConfig, Int32& pnButton, Int32& pnRadioButton, Boolean& pfVerificationFlagChecked)
   at Ookii.Dialogs.Wpf.TaskDialog.ShowDialog(IntPtr owner) in F:\Demos\ookii-dialogs-wpf\src\Ookii.Dialogs.Wpf\TaskDialog.cs:line 1147
   at Ookii.Dialogs.Wpf.TaskDialog.ShowDialog(Window owner) in F:\Demos\ookii-dialogs-wpf\src\Ookii.Dialogs.Wpf\TaskDialog.cs:line 1095
   at AMDownloader.Views.MainView.AboutMenu_Click(Object sender, RoutedEventArgs e) in AM Downloader\Views\MainView.xaml.cs:line 213
   at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
   at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
   at System.Windows.Controls.MenuItem.InvokeClickAfterRender(Object arg)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at System.Windows.Threading.DispatcherOperation.InvokeImpl()
   at MS.Internal.CulturePreservingExecutionContext.CallbackWrapper(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at MS.Internal.CulturePreservingExecutionContext.Run(CulturePreservingExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Windows.Threading.DispatcherOperation.Invoke()
   at System.Windows.Threading.Dispatcher.ProcessQueue()
   at System.Windows.Threading.Dispatcher.WndProcHook(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
   at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)
   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
   at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
   at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
   at System.Windows.Application.RunDispatcher(Object ignore)
   at System.Windows.Application.RunInternal(Window window)
   at AMDownloader.App.Main()

Findings:
Except Autodesk Revit 2025, other 3 WPF applications are referencing Ookii.Dialogs.Wpf nuget package and issue occurs when calling TaskDialog.ShowDialog() method from the package.
After debugging into the source code of Ookii.Dialogs.Wpf nuget package, we find the issue occurs when calling TaskDialogIndirect() method, which is imported from comctl32.dll. (in "ookii-dialogs-wpf\src\Ookii.Dialogs.Wpf\NativeMethods.cs" file)

[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Interoperability", "CA1400:PInvokeEntryPointsShouldExist"), DllImport("comctl32.dll", PreserveSig = false)]
public static extern void TaskDialogIndirect([In] ref TASKDIALOGCONFIG pTaskConfig, out int pnButton, out int pnRadioButton, [MarshalAs(UnmanagedType.Bool)] out bool pfVerificationFlagChecked);

For Autodesk Revit 2025, it also shows the exception is related to TaskDialog in the application log (Full log file attached: journal.0001.txt):

'DefaultButton : Close
  'C 10-Jun-2025 05:37:10.118;  DBG_WARN: TaskDialog Exception:
  'Value does not fall within the expected range.: line 92 of F:\Ship25.4\2025_px64\Source\UIFramework\UIFrameworkInterop\TaskDialog\AdWindowsTaskDialog.cpp.
  'C 10-Jun-2025 05:37:10.121;  DBG_WARN: TaskDialogResult should always be a positive number: line 270 of F:\Ship25.4\2025_px64\Source\UIFramework\UIFrameworkInterop\TaskDialog\AdWindowsTaskDialog.cpp.
'C 10-Jun-2025 05:37:10.121;   0:< Process result of DebugModes-Changed Task Dialog

@dotnet-actwx-bot @dotnet/compat

[Junjun-zhao]

Hi @harshit7962, could you please take a look at this issue? So far, it has affected 4 apps in our lab.

[harshit7962]

@Junjun-zhao, it appears that the issue is not related to WPF. Upon investigating the failure, the E_INVALIDARG exception is being thrown from the comctl32 dll. This is due to the invalid cbsize attribute of TaskDialogConfig, which is being initialized here.

I have reviewed the initialization of this value in .NET 9, .NET 10 - preview 5, and .NET 10 - preview 6. The value after the call to Marshal.SizeOf(_config) is expected to be 160 as in .NET 9 and preview 5 of .NET 10. However, in preview 6, it comes out to be 176. The comctl32.dll expects the value to be 160, and this mismatch causes the application to crash.

It seems like this could be due to changes in calculation of SizeOf call. Based on these findings, transferring this issue to runtime.

[huoyaoyuan]

The interop struct is generated by CsWin32. The definition is:

		internal partial struct TASKDIALOGCONFIG
		{
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">UINT</a></b> Specifies the structure size, in bytes.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal uint cbSize;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">HWND</a></b> Handle to the parent window. This member can be <b>NULL</b>.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.HWND hwndParent;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">HINSTANCE</a></b> Handle to the module that contains the icon resource identified by the <b>pszMainIcon</b> or <b>pszFooterIcon</b> members, and the string resources identified by the <b>pszWindowTitle</b>, <b>pszMainInstruction</b>, <b>pszContent</b>, <b>pszVerificationText</b>, <b>pszExpandedInformation</b>, <b>pszExpandedControlText</b>, <b>pszCollapsedControlText</b> or <b>pszFooter</b> members.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.HINSTANCE hInstance;
			/// <summary>
			/// <para>Type: <b>TASKDIALOG_FLAGS</b> Specifies the behavior of the task dialog. This parameter can be a combination of flags from the following group: </para>
			/// <para>This doc was truncated.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.UI.Controls.TASKDIALOG_FLAGS dwFlags;
			/// <summary>
			/// <para>Type: <b>TASKDIALOG_COMMON_BUTTON_FLAGS</b> Specifies the push buttons displayed in the task dialog. If no common buttons are specified and no custom buttons are specified using the <b>cButtons</b> and <b>pButtons</b> members, the task dialog will contain the <b>OK</b> button by default. This parameter may be a combination of flags from the following group: </para>
			/// <para>This doc was truncated.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.UI.Controls.TASKDIALOG_COMMON_BUTTON_FLAGS dwCommonButtons;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used for the task dialog title.  This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro. If this parameter is <b>NULL</b>, the filename of the executable program is used.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszWindowTitle;
			internal winmdroot.UI.Controls.TASKDIALOGCONFIG._Anonymous1_e__Union Anonymous1;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used for the main instruction. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszMainInstruction;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used for the dialog's primary content. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro. If the ENABLE_HYPERLINKS flag is specified for the <b>dwFlags</b> member, then this string may contain hyperlinks in the form: &lt;A HREF="executablestring"&gt;Hyperlink Text&lt;/A&gt;.  <b>WARNING: Enabling hyperlinks when using content from an unsafe source may cause security vulnerabilities.</b></para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszContent;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">UINT</a></b> The number of entries in the <b>pButtons</b> array that is used to create buttons or command links in the task dialog. If this member is zero and no common buttons have been specified using the <b>dwCommonButtons</b> member, then the task dialog will have a single <b>OK</b> button displayed.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal uint cButtons;
			/// <summary>
			/// <para>Type: <b>const <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/ns-commctrl-taskdialog_button">TASKDIALOG_BUTTON</a>*</b> Pointer to an array of <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/ns-commctrl-taskdialog_button">TASKDIALOG_BUTTON</a> structures containing the definition of the custom buttons that are to be displayed in the task dialog.  This array must contain at least the number of entries that are specified by the <b>cButtons</b> member.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal unsafe winmdroot.UI.Controls.TASKDIALOG_BUTTON* pButtons;
			/// <summary>
			/// <para>Type: <b>int</b> The default button for the task dialog.  This may be any of the values specified in <b>nButtonID</b> members of one of the <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/ns-commctrl-taskdialog_button">TASKDIALOG_BUTTON</a> structures in the <b>pButtons</b> array, or one of the IDs corresponding to the buttons specified in the <b>dwCommonButtons</b> member: </para>
			/// <para>This doc was truncated.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal int nDefaultButton;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">UINT</a></b> The number of entries in the <b>pRadioButtons</b> array that is used to create radio buttons in the task dialog.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal uint cRadioButtons;
			/// <summary>
			/// <para>Type: <b>const <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/ns-commctrl-taskdialog_button">TASKDIALOG_BUTTON</a>*</b> Pointer to an array of <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/ns-commctrl-taskdialog_button">TASKDIALOG_BUTTON</a> structures containing the definition of the radio buttons that are to be displayed in the task dialog.  This array must contain at least the number of entries that are specified by the <b>cRadioButtons</b> member. This parameter can be <b>NULL</b>.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal unsafe winmdroot.UI.Controls.TASKDIALOG_BUTTON* pRadioButtons;
			/// <summary>
			/// <para>Type: <b>int</b> The button ID of the radio button that is selected by default. If this value does not correspond to a button ID, the first button in the array is selected by default.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal int nDefaultRadioButton;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used to label the verification checkbox. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro. If this parameter is <b>NULL</b>, the verification checkbox is not displayed in the task dialog. If the <i>pfVerificationFlagChecked</i> parameter of <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/nf-commctrl-taskdialogindirect">TaskDialogIndirect</a> is <b>NULL</b>, the checkbox is not enabled.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszVerificationText;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used for displaying additional information. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro.   The additional information is displayed either immediately below the content or below the footer text depending on whether the TDF_EXPAND_FOOTER_AREA flag is specified.  If the TDF_ENABLE_HYPERLINKS flag is specified for the <b>dwFlags</b> member, then this string may contain hyperlinks in the form: &lt;A HREF="executablestring"&gt;Hyperlink Text&lt;/A&gt;. <b>WARNING: Enabling hyperlinks when using content from an unsafe source may cause security vulnerabilities.</b></para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszExpandedInformation;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used to label the button for collapsing the expandable information. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro. This member is ignored when the <b>pszExpandedInformation</b> member is <b>NULL</b>.  If this member is <b>NULL</b> and the <b>pszCollapsedControlText</b> is specified, then the <b>pszCollapsedControlText</b> value will be used for this member as well.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszExpandedControlText;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer that references the string to be used to label the button for expanding the expandable information. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro. This member is ignored when the <b>pszExpandedInformation</b> member is <b>NULL</b>.  If this member is <b>NULL</b> and the <b>pszCollapsedControlText</b> is specified, then the <b>pszCollapsedControlText</b> value will be used for this member as well.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszCollapsedControlText;
			internal winmdroot.UI.Controls.TASKDIALOGCONFIG._Anonymous2_e__Union Anonymous2;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">PCWSTR</a></b> Pointer to the string to be used in the footer area of the task dialog. This parameter can be either a null-terminated string or an integer resource identifier passed to the <a href="https://docs.microsoft.com/windows/desktop/api/winuser/nf-winuser-makeintresourcea">MAKEINTRESOURCE</a> macro. If the TDF_ENABLE_HYPERLINKS flag is specified for the <b>dwFlags</b> member, then this string may contain hyperlinks in this form.</para>
			/// <para></para>
			/// <para>This doc was truncated.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.Foundation.PCWSTR pszFooter;
			/// <summary>
			/// <para>Type: <b>PFTASKDIALOGCALLBACK</b> Pointer to an application-defined callback function. For more information see <a href="https://docs.microsoft.com/windows/desktop/api/commctrl/nc-commctrl-pftaskdialogcallback">TaskDialogCallbackProc</a>.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal winmdroot.UI.Controls.PFTASKDIALOGCALLBACK pfCallback;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">LONG_PTR</a></b> A pointer to application-defined reference data. This value is defined by the caller.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal nint lpCallbackData;
			/// <summary>
			/// <para>Type: <b><a href="https://docs.microsoft.com/windows/desktop/WinProg/windows-data-types">UINT</a></b> The width of the task dialog's client area, in dialog units. If 0, the task dialog manager will calculate the ideal width.</para>
			/// <para><see href="https://docs.microsoft.com/windows/win32/api//commctrl/ns-commctrl-taskdialogconfig#members">Read more on docs.microsoft.com</see>.</para>
			/// </summary>
			internal uint cxWidth;

			[StructLayout(LayoutKind.Explicit, Pack = 1)]
			[global::System.CodeDom.Compiler.GeneratedCode("Microsoft.Windows.CsWin32", "0.2.63-beta+89e7e0c43f")]
			internal partial struct _Anonymous1_e__Union
			{
				[FieldOffset(0)]
				internal winmdroot.UI.WindowsAndMessaging.HICON hMainIcon;
				[FieldOffset(0)]
				internal winmdroot.Foundation.PCWSTR pszMainIcon;
			}

			[StructLayout(LayoutKind.Explicit, Pack = 1)]
			[global::System.CodeDom.Compiler.GeneratedCode("Microsoft.Windows.CsWin32", "0.2.63-beta+89e7e0c43f")]
			internal partial struct _Anonymous2_e__Union
			{
				[FieldOffset(0)]
				internal winmdroot.UI.WindowsAndMessaging.HICON hFooterIcon;
				[FieldOffset(0)]
				internal winmdroot.Foundation.PCWSTR pszFooterIcon;
			}
		}

HWND, HINSTANCE, HICON and PCWSTR are simple wrappers of IntPtr/char*.

The struct contains 2 unions of pointer-sized fields, and the new size grows by 2 pointers.

#113454 is suspectable. @jkoritzinsky