... it only happens in opera. Opera is iirc Chrome-based browser, and chrome works perfectly fine (tho i can't use multiple tabs on it, eats RAM alive)

Both Opera and Chrome are based on Chrome's Blink rendering engine. But in Opera, between that engine and the user lies a user interface layer and overall browser integration techniques that reflect Opera's way of implementing various features and user controls, differing from what exists in Chrome's own implementation. The browsers perform and operate differently because they are different in many ways, apart from their shared code, as you and others have observed. Those differences can and do cut both ways. Obviously, from different user standpoints, both Opera and Chrome have differing areas needing improvement. The question is whether their respective design teams view those needs the same way as the user, at least in terms of expending designer resources in those directions as compared with other possible areas.