It's a running problem and has happened ever since I got Roundcube installed on my cPanel. Basically, when I go into it, there are messages in my inbox and I can view them. But when I got into other folders there are no messages. If I click back to inbox, there are now no messages.
Back to the inbox, when the messages are displayed, if I delete some, and then go to the trash folder, they won't be in there and then they will be back in the inbox.
I hope there is a fix for this as I cannot use RoundCube with this running problem.