@pindos Are you sure you are talking about maximized opera window ? Because i have these buttons too, until the window is maximized!
regular view
0_1547975825169_1349c63c-9825-46ca-9274-5d1093cf5e6e-image.png
maximized view
0_1547975841833_225bcd9f-c7fb-4c28-b198-d3bdbe975df0-image.png