Ahhh, Bluestacks. My favorite turd of a program. Honestly, I love running my Android Apps on my Windows devices, but wow is this program slow, and full of bugs. Anyway, it’s still the best at what it does, so I am using it on my Dell Venue 8 Pro Tablet. However, out of the box, the orientation seemed the opposite of what you would want it to be, making the program use only about a 1/3rd of the screen at any given time. There is however, a pretty easy fix for this problem. Open up regedit and go to the following location:
Edit the following keys to the noted values (in decimal)
1200 for height
800 for width
That’s it, close regedit, restart your tablet, and happy Androiding!