Hi,
I have set mercury to save PDF-attachments from e-mails. Now Mercury should "Highlight" this e-mail in colour red. Unfortunately, the function is not executed.

If I use the Filter-action "Add a header to the message" (X-PMFLAGS: 128 1), the e-mail is displayed in red, but unfortunately the formatting does not fit for some emails.
Is there a way to insert X-PMFLAGS: without formatting the email?

I saw that this question has not received any responses so I am posting with my thoughts. First, I assume that the intent of the red color is to call attention to the fact that a pdf attachment was saved. I have been away from Mercury too long to remember all of the filter actions so let me describe how I handled .zip attachments for my company.

I blocked all .zip attachments by using a filter to save them as a file and remove them from the email. To notify the employee, I used another filter to add a text fragrant to the message that said something like "A .zip file has been removed from this message. Contact the IT department for its review and release."