GeckoFx60 messing with Outlook decimals

Question

I'm implementing GeckoFx60 in an Outlook VSTO solution. As soon as I call the Xpcom.Initialize() method, all the decimals in Outlook change.

For example, the reminder dialog suggests postponing a meeting reminder for 5,00000000000 minutes. Also, the weather forecast changes from 17 degrees Celcius to 17,00000000000 degrees Celcius.

With GeckoFX45 everything is fine, but I need GeckoFx 60.

Example:

It is fairly easy to reproduce the issue:

• Open Visual studio 2013
• New project
• Visual C# > Office/Sharepoint > Outlook 2013 add-in
• Edit csproj file and Change DebugInfoExeName from Office\15.0\Outlook\InstallRoot to Office\16.0\Outlook\InstallRoot
• Change the projects targeted framework to .NET Framework 4.5
• Nuget package manager > install geckofx-60 Windows 32bit
• Change the ThisAddIn_Startup

        [STAThread]
        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            Xpcom.Initialize("Firefox");
        }

If you launch Outlook, the decimals are changed. Thread.CurrentThread.CurrentCulture and Thread.CurrentThread.CurrentUICulture are still the same before and after Initialize is called.

Even threaded, the same isses exists:

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            Thread thread = new Thread(init);
            thread.TrySetApartmentState(ApartmentState.STA);
            thread.Start();
        }

        private void init()
        {
            Xpcom.Initialize("Firefox");

        }

Answer 1

To self answer my question :) I did a lot of research and testing on this subject. I've tried XulFx with firefox-sdk 52 and experienced exactly the same issue. There are several topics about this at Microsoft and Apple; this issue also existed when Apple iCloud was used in combination with Microsoft Outlook.

https://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook-mso_winother-mso_365hp/outlook-application-number-format/e8442cd7-4903-4317-b2b9-0fbf9c260cde https://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook-mso_windows8-mso_2013_release/outlook-2013-gives-12-decimals-after-the/517799f8-58bb-4d31-a32d-85ab20fb0286 https://social.technet.microsoft.com/Forums/office/en-US/765eef7e-3d86-4fdb-8e86-04342b882698/too-many-decimals-zeros-show-in-outlook-calender?forum=outlook https://discussions.apple.com/thread/6693701 https://discussions.apple.com/thread/8089708

I just gave up and switched to Microsoft's WebView2 component. (https://learn.microsoft.com/en-us/microsoft-edge/webview2/gettingstarted/winforms)