I often have many regular, and incognitos open, but with opera GX it is more difficult to discern than it should be when alt-tabbing, or using the task bar.

Please give us a different colour scheme for the incognito window, and / or the ability the change the colour scheme for the incognito window separately. Even if you want to force a black-based colour scheme, even having the outline colour (which we are choosing anyway) different would help a LOT.