[kristop]

You can switch the active annotation layer with a touch action though ...

You can toggle the visibility of individual layers in the annotations editor by bringing up the layers window and tapping the eye icon next to a layer.

Thanks for the answer.
Yes using the annotations editor and the eye icons is what I currently do.

But what do you mean by " You can switch the active annotation layer with a touch action though " : can I do that in Concert mode ? How ?