title: Unity - OnDrag / IDragHandler not working on mobile
body: <p>I developed my game in Unity 5, I could drag my joysticks and any Ui normally on Mobile and editor. Since I updated to Unity 2019, Ui drag works only in editor and NEVER on Mobile touch, keep in mind: 
  ✅ EventSystem is implemented in Canvas 
  ✅ My code worked perfectly in Unity 5, and i never touched it 
  ✅ I have Physics 2D Raycaster on my Camera 
  ✅ Raycast Target are enabled inside my Joystick Ui image. 
   Help is appreciated, since i did not sleep a minute the last 19 hours trying to find a solution.</p>