c# Display custom note at the top of outlook message after message have been processed by plugin

Question

I've seen other outlook plugins that modify an e-mail item to display a note at the top of the e-mail. Look at this image:

I have an outlook plugin written in c# (using Microsoft.Office.Interop.Outlook) and the Microsoft.Office.Tools. When a user has pushed the plugins button (in my case to transfer attachments to another application) I would like to add such note at the top. This way the user can see that the mail message has already been processed with the plugin. But I have no clue what to look for in the Outlook.MailItem to set such message in the top of the mail. Can anyone tell me how to do this. A piece of code will be fine, but just the name of the feature could be enough to find code samples online.

Answer 1

That band is simply a category; you can modify it using the MailItem.Categories property: https://msdn.microsoft.com/en-us/library/ff869685.aspx