Turning off gradients on tab empty space and toolbars

Is there any way to turn off the gradient on tabs empty space and the toolbar with back/forward, address bar and such? They are not present in customize > toolbars to disable any image that would be applied, and I find it ugly and completely unfitting with the flat aspect on everything else. I already unchecked the "Use visual style to draw items" option.

Preferences / Miscellaneous / Advanced: gloss_and_gradients

That did the trick, thanks!