Comment 6 for bug 751450

nb. to self/others, the theme override code in Unity-3D is currently:

    319 // FIXME: we need to create some kind of -unity postfix to see if we are looking to the unity-icon-theme
    320 // for dedicated unity icons, then remove the postfix and degrade to other icon themes if not found
    321 if (((g_strrstr (icon_name, "user-trash") != NULL) ||
    322 (g_strcmp0 (icon_name, "workspace-switcher") == 0)) &&
    323 IsMonoDefaultTheme ()) {
    324 result = TextureFromSpecificGtkTheme (_unity_theme, icon_name, size, update_glow_colors);

Note that the assets in question were delivered containing a background, which should not have been the case and is being dealt with.