Hello,

This Feature Request's status will be changed to Declined.

The existing Office 2019 theme and its Light ColorVariation can be easily customized to achieve the MS Office White theme. The brushes of the Light Palette that need to be modified are the following - ButtonBackgroundColor, BaseBackgroundColor, AlternativeBackgroundColor and SecondaryBackgroundColor. An example follows:

Office2019Palette.LoadPreset(Office2019Palette.ColorVariation.Light);
Office2019Palette.Palette.ButtonBackgroundColor = (Color)ColorConverter.ConvertFromString("#FFFFFFFF");
Office2019Palette.Palette.BaseBackgroundColor = (Color)ColorConverter.ConvertFromString("#FFFFFFFF");
Office2019Palette.Palette.AlternativeBackgroundColor = (Color)ColorConverter.ConvertFromString("#FFFAFAFA");
Office2019Palette.Palette.SecondaryBackgroundColor = (Color)ColorConverter.ConvertFromString("#FFF1F1F1");

This custom Office 2019 White theme can also be found in the updated version of our Color Theme Generator application, where you can adjust all theme palette properties up to your needs.

Best regards,
Vicky
Progress Telerik