Mail not being shown

[Allan Nicholles]

I've downloaded the FREE version of Maildroid (2.77) for my Kindle Fire HD. I quite like the layout and functionality. I have three accounts set up to use this application. One works well, but another has an annoying problem which I'm hoping for help with. When a mail is delivered to that account it shows in both the combined inbox as well as the account inbox. However, after I've opened the mail it disappears from the inbox of both the account inbox and the combined one. I can't find it anywhere. Does anyone know what causes this and what can be done to prevent it?