How to add a button to the inline "Message" ribbon in outlook?

Question

I've successfully added a new button to the Message ribbon in Outlook for sending new messages or when using the pop out feature to reply to messages by creating a custom ribbon/button in C# in VS but can not for the life of me figure out how to get that same button on the Message ribbon that appears when replying to a message inline. Is there a particular ribbon control id I need to use? I have been unable to find any useful information about it online anywhere.

Answer 1

You need to use the TabComposeTools idMso value for the tabSet attribute and the TabMessage value for the IdMso property of the tab attribute. For example, you can use the following markup:

<customUI onLoad="Ribbon_Load" xmlns="http://schemas.microsoft.com/office/2006/01/customui">
<ribbon>
    <contextualTabs>
        <tabSet idMso="TabComposeTools">
            <tab idMso="TabMessage">

            // your controls go there

            </tab>
        </tabSet>
    </contextualTabs>
</ribbon>

See Contextual tab for the Outlook inline response in Explorer windows. for more information.