On Xtreamer Prodigy MENU (6) key is one of the most important remote buttons. Generally in the Media Library it gives you access to viewing options, allows you to add files and folders to favorites, setup NFS shares and so on.
Pressing the button will open a panel on the right fide.
In can also be used while playing a movie to toggle a list of various options including 3D playback option.
While running an image slideshow MENU key can also provide some additional features.
Slidewhow timing
Transition options
And specify background music
The FUNC button on the other hand takes on the full file manager role and allows you to copy, move or delete files (single or multiple) and so on.