[Retina MacBook Pro 15, model 10,1]Since installing El Capitan, iBooks opens and allows me to see my library, download existing purchases etc, but won't let me read any of them:- open iBooks- double-click on any of the books (for example The Swift Programming Language from Apple)- mouse cursor disappears- nothing else happensAfter that,- moving the mouse restores the mouse cursor- iBooks seems to continue functioning normally (you can select books, change category etc) apart from this inability to open a bookAnyone else?