As of today's date - Aug. 13, 2015 - Here's how to sort bookmarks in Opera:
- Bring up a new Opera browser tab.
- Left click on the Opera icon in the upper left corner of screen.
- Click "Bookmarks" in the drop down manu
- Hover over "My Folders" in the "Bookmarks drop down menu.
- Right click on "My Folders"
- Select "Sort alphabetically in the drop down menu.
- Enjoy your sorted bookmarks!