Hello There,
The same problem is what I have faced before and found the solution to it. Let me tell you theirs some instruction which you have to follow, some basic instruction and I hope it will work...
First Just go to bookmark menu there you will see an option at the top of the left opera Icon...
Lets say I have a 2 pages bookmark to my browser 1. Iraqi Dinar and other one 2. Opera
Then just by clicking on that opera icon, you will the folders with which you have bookmarked to your browser, right click on the folder which you want to see on top or you can set priority there as well.
Hope you got my... Enjoy your Opera