Thank you a lot.
It seems to me, that ist only works fine with C4D native materials and not Corona or other renderer.
With right click on the Corona material, there you can see the list with different projections.
Most of these previews are too small and I always have to popup a new window to see that texture larger, although it is the largest size.
Image I1 is what you can see now, and I2 is what I would like to have
F.