widget.newButton shown in simulator but not on device

In corona simulator I can see the buttons, but on the actual device I don’t see them.

not sure what’s wrong, no errors in console.

        local function playBtnF(event)             if( "ended" == event.phase ) then                 transition.to(menuScreenGroup,{time=0, alpha=0, onComplete=addGameScreen})             end         end                  local playBtn = widget.newButton{             left = display.contentCenterX,             top = 0,             id = "playbutton",             label = "Play",             onEvent = playBtnF         }  

EfrEV.png