Cockpit: why are not all Media shown in the 'Media' selection pop-ups?

This article explains what the reason is for missing Media in the 'Media' selection pop-ups in the Booking Cockpit and how to resolve the issue. It is possible that due to rights assignment settings Users with a certain 'Function' (e.g. Admin) do see it and Users with another 'Function' not.  

With click on 'Media' in the Optimizer / Rebook / Documents tab of the Booking Cockpit, the pop-up for Media selection opens. In the example used in this FAQ article, the newly created Media 'test' is not shown.

Once Media are created, in the Cockpit an order in which the corresponding Media is stored must be selected. With this action, the necessary rights are created. In the following, the Media will be shown in the selection pop-ups.