Signage Player is a program created by MediaSignage which is available for free and allows the user to set up linux or windows pcs that display advertisement or other sorts of content in slideshows etc.
The player launches after the pc does and starts displaying its campaign in fullscreen. If you use an older version of linux it will automatically remove the gnome-panel (the taskbar) if you selected that option during installation.
If you did not select that option or are using a new linux version with a more recent gnome ui, the player will not remove the panel.
If the panel is not removed the player will still launch in full screen but the panel will be visible. The player can be brought to the front by clicking the mouse once, but naturally in a real environment you want it to launch into proper fullscreen because nobody will be there to click anything. What's needed is a script solution that will automatically give focus to the player window (which is what happens when you click inside that window manually) so the player will be brought to the front and the gnome panel will become invisible.