I have a opengl window and you can choose your colordepth with a setup program. With 16 and 32 bits it works fine but with 24 not. Is that not supported. I always thougt you could set your resolution to 24 bits or must you do something special for that? Thanx in advance

Since 32 bits color depth is usually much faster than 24 bits (due to bytes alignement), lots of graphic cards does not even support it. Some support it but are *really* slow in 24 bpp mode and fast in 32 bpp. It is not an OpenGL issue but rather a card manufacturer one.