glcolor4f and lighting_enabled

Hello,
I am trying to write a custom jit.gl object. In my drawing function I draw a rectangle as follows:
t_jit_err jit_gl_simple_draw(t_jit_gl_simple *x)
{
    t_jit_err result = JIT_ERR_NONE;
    glBegin(GL_QUADS);
glColor4f(0.5, 0.3, 0.7, 0.2);
    glVertex3f(-1,-1,0);
glColor4f(0.5, 0.3, 0.2, 0.2);
    glVertex3f(-1,1,0);
glColor4f(0.5, 0.1, 0.2, 0.2);
    glVertex3f(1,1,0);
glColor4f(0.2, 0.1, 0.2, 0.2);
    glVertex3f(1,-1,0);
    glEnd();
    return result;
}

If I have lighting_enabled set to 0, I'll see the color. But when lighting_enabled set to 1, it turns into grayscale. Does anyone know what I am missing? Any advices would be very appreciated!

cheers,
mf