Most probably, you are reading this post because you don't want VLC from opening multiple Windows while playing music. For example, you opened a song in VLC, then when you open another song, the previous one will continue playing. so two songs simultaneously. This is really irritating.
But not to worry. It is just the default setting in Ubuntu and can be changed very easily from the preferences menu. just Open "VLC media Player>Tools>Preferences". Then under "Interface" tab, you will find a section named "Instances". Now just check "Allow only one instance" and you are done.