I use a laptop running xubuntu 3.10. When I compile a C# or C++ program with gtk that contains just any message dialog, then the icon in the dialog is always gray only. No colors. While in similar examples on the internet these icons are colorful. This happens independently of the theme. If other themes are used, then the gray saturation changes, but there is still no color. When I delete gtk-2.0 and gtk-3.0 in the .config file, there is no difference. Still no color.