Found it. Solved it. Just apply the patch to "/usr/share/themes/Radiance/gtk-2.0/gtkrc".
It somehow works instantly, i.e. it changes the appearance of the menu bar instantly. Don't know why ... Caveats: 1) It's still called Radiance and not Bright. 2) One might still perceive some kind of embossed or glossy effect: maybe that's a perceptive interference with the background gradient but it doesn't show up in the pixel values. (This might even depend on the type of display - not all liquid crystal display show a static image: some try to interpolate unrepresentable colors of RGB24 by alternating rapidly between two colors in 6 bit color channels bla bla etc.) ** Patch added: "Patch (created with diff -u): set RGBA to false in gtkrc" https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1465340/+attachment/4415219/+files/radiance-menu.patch -- You received this bug notification because you are a member of DX Packages, which is subscribed to unity in Ubuntu. Matching subscriptions: dx-packages https://bugs.launchpad.net/bugs/1465340 Title: Unity Radiance Menu Bar Should Stop Radiating Status in unity package in Ubuntu: New Bug description: This bug has been there for at least three years. The font anti aliasing in the menu bar is completely off when the user chooses the Radiance theme. The attached screen shot shows a Firefox menu on top of an Emacs session. You see the unity menu bar at the top with the distorted anti aliasing. Under it in the pop-up menu you see a font rendered normally which looks much better. In addition to the distorted anti aliasing the menu bar does not seem to respect the user settings in "~/.fonts.conf". Please fix this and alter the name of Radiance to "Bright". Stop the menu bar from radiating with Radiance. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/unity/+bug/1465340/+subscriptions -- Mailing list: https://launchpad.net/~dx-packages Post to : dx-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~dx-packages More help : https://help.launchpad.net/ListHelp