Awesome! (There is actually a way to add attachments!)

This app is so handy! If you really must add attachments to your emails, you can go to the very main screen and scroll all the way down to the bottom. Once there, there’s a little thing that says "View gmail in:” click on desktop. Then reply or compose a new message there and you will be able to add attachments! Simple!

Simply Curious about MailTab for Gmail - Email Client, v6.1