I have to stop playback for the sound "waves" to generate in FCPX?

Hi there everyone!

I was wondering something that has been bothering me for a while now when I am editing sound on FCPX: I always have to pause my playback for the audio "waves" to generate, so I can see where my gaps and silences are. Isn't there any option on FCPX for it to appear automatically while playing the clip? I joined a screen capture of the problem, I have to stop my playback for the gaps to fill with the audio 

Thanks for your help !

Absolutely, you have to stop,, and it's for the best because every ressource is mobilized when playing.