I played with settings (changed a lot of 'em) and once I applied 'em, window title become black (but tab pages still drawn grey). Also black background start visible under pop-up menu (you see it as a black frame around menu). Why it happens and why Opera cannot use normal, standard controls? Is it so necessary to draw everything by yourself??? As you see, you just break everything! Instead of seeing standsrd Window popup, I see annoying custom drawn black frame and popup inside. Same about window title - all standard buttons (min/max/close) become completely invisible (I suppose they are drawn with black ink on black background).
Where is that ugly code, which I should switch off?
Just found that bug - it's Vulkan API! Switch this cr@p off and everything become OK.