As many of you know that PDF Kneeboard no longer works in V4, I was looking through internet to eliminate that problem and have found the program called "Always-On-Top".
Here is the video on how to use it, easy as 1-2-3.
You can download it here:
https://img.labnol.org/di/always-on-top.zip?_ga=2.172835363.1086715399.1510970198-244909298.1510847850