[Swiss1000]

It is an option my drumer speak about : with pedal switch, imagine to display or remove notes of the active musicscore ?
Sometime, musicians have notes to remember, they don't need to display it all the time.  ?

IMHO there is no need for an additional option/feature like this.
If you don´t need your notes, just ignore it. Or, delete it (in preparation of rehearsals or stage or whatever).
Further, there is an option "show notes when loaded", check/uncheck it, as needed.
e.k.

Well, it's perhaps worth thinking about. 

So far, we each have a main score, alongside a page for the lyrics, and he adds a page for drum specifics (intro, outro, rhythm type, etc.). He uses a drum switch attached to the snare drum that moves forward and backward. He would prefer to temporarily display annotations. He did this with the setlist and song lyrics display, but we need them too. 

It might be cool to temporarily display annotations transparently and be able to remove them...