Hi olivier feller,
While there is not an out of the box option to remove this from the UI, there are a couple of options available to you if this is a feature you are interested in.
1. If you would like to see this as an option in a future release, I would recommend submitting an idea to the Ideas for Jive space where our product managers review through to rated ideas when considering features for future releases.
2. If you are interested in removing this form your current instance our Professional Services team can assist in determining the scope of the project and assist in implementing a custom feature for your instance if available. If you would like to pursue this option, please either reach out to your account manager, or submit a case in your customer group here in the Jive Community and a member of our support team can get an engagement started for you.