SetSignature gets styles overwritten when a normalemail.dotm file is present in Outlook Desktop (classic)

[bogdanst24]

Your Environment

• Platform [PC desktop, Mac, iOS, Office on the web]: PC Desktop
• Host [Excel, Word, PowerPoint, etc.]: Outlook (classic/legacy)
• Office version number: Any
• Operating System: Windows

Expected behavior

The result is consistent regardless of the Platform when using the setSignature API with any HTML.

Current behavior

When having a template set for new documents (emails) in Outlook in the form of a custom normalemail.dotm file, then the signature inserted will inherit the document's styles. It is not the same when:

• using Web Add-ins in Outlook Online, even though a custom style is set for any new emails
• using Outlook's native signatures when having a custom template for new emails

As this makes web add-ins inconsistent across different platforms and does not provide the expected results in the classic Outlook for Windows, this should be fixed. This is preventing customers from migrating from VSTO-based add-ins to Web add-ins.

Steps to reproduce

1. Set up a custom template applied to new documents (update normalemail.dotm file). Can be easily tested with line spacing set to e.g. 40pt.
2. Use Script Lab for Outlook
3. Insert a signature using the "Work with client signatures (compose)" sample. The signature will inherit the styles. If custom styles are provided using HTML, then those will be overwritten when inserted.