I don't like tabs this way, using a mouse isn't useful because you have be very accurate to click on tabs, default tabs place are easly since you are limited with the top of the screen, the only way for me would be moving the OS taskbar on top and the tabs to the down edge.
Windows 10 (x64) | Anniversary Update
Opera Stable · Beta · Developer
That suggestion it's only for Android and Youtube - despite the PC option, you need BluStacks or Memu -, @dasimbg is asking about Opera Desktop version.