Remove ancient Exec= key from .desktop file.
Should allow JuK to start on Wayland. Should also allow arguments to be passed to JuK (which in theory supports loading files from command line). I ask for URLs to be passed (%U) instead of files (%F) to avoid over-eager file managers or desktops trying to download music files to a temp directory and then deleting them once JuK is done. GUI: BUG:391354 FIXED-IN:18.04