fixes #62 (z-index stacking order due to CSS GPU hardware acceleratio…

…n, which is needed to fix a blocking bug (clipped rendering) in WebView OSX in native Readium launchers)

js/views/scroll_view.js

@@ -73,6 +73,10 @@ ReadiumSDK.Views.ScrollView = function(options, isContinuousScroll){
         _$contentFrame.css("height", "100%");
         _$contentFrame.css("position", "relative");
 
+        // This is a necessary counterpart for the same CSS GPU hardware acceleration trick in one_page_view.js
+        // This affects the stacking order and re-enables the scrollbar in Safari (works fine in Chrome otherwise)
+        _$contentFrame.css("transform", "translateZ(0)");
+
         // _$contentFrame.css("box-sizing", "border-box");
         // _$contentFrame.css("border", "20px solid red");