I have an VSTO Outlook Addin and I would like to know how can I change the font color of some email addresses (To:) in the compose window. Is that possible? If so how?
I want to avoid using custom form regions.
The Outlook extensibility model doesn't provide anything for that.
The best what you could do is to create a form region based on the replacement layout which substitutes the built-in controls. Be aware, you need to implement all the fields on your own in that case. A replacement form region is a page that replaces the default page of a standard form, and a replace-all form region replaces all pages in a standard Outlook form. See Walkthrough: Design an Outlook form region for more information.