Gmail extension/gadget API - how to add a button to the compose toolbar?
I'm trying to figure out how can I add a button to the Gmail compose window. In "Gmail Labs" they have some extensions that add certain buttons For example "Send & Archive" button and "Inserting images" button, so I assume this is possible. I checked their API here and it seems that you can either add a gadget to left sidebar or use contextual gadgets that are dependent on the message context. I'm looking for a way to add a button to the toolbar of the compose window, and both options don't seem to support it. Do you know how can this be done? If it's not possible using Gmail API, is there