Color bar in snap-9

Can we put color bar in the product map of SENTINEL-3/OLCI in SNAP-9.0.0. I am unable to find it!

Unfortunately, this is not easily doable.
You can export the color bar as image (right click on scene image) and then add this image as layer to the scene. But finding a good scaling and position is quite tedious.
It is easier if you do it externally if you want to have an image in the end.