src/macosx/classes/com/apple/laf/AquaScrollPaneUI.java

@@ -58,8 +58,11 @@
             super.mouseWheelMoved(e);
 
             if (wasVisible) {
                 vScrollBar.setVisible(true);
             }
+            // Consume the event even when the scrollBar is invisible
+            // see #7124320
+            e.consume();
         }
     }
 }