I have a Microsoft Sculpt wireless keyboard with separate keypad. I'm working with Windows 10 Pro on a Dell Ultrabook, Intel I5 64bit X64 and O365 and Office 2016. I also have two screens in addition to the laptop screen.
My problem is, when I change screen or window and start to type, the keyboard misses the first letter... each and every time. I also have this keyboard and mouse package at home on a Dell desktop with the same operating systems and office package and it does exactly the same thing. Even in this window, when I clicked on another screen and back again, and started typing, the first letter was missed.
Unfortunately, my Ultrabook is a work laptop and therefore I have no admin rights, however, if someone can make a suggestion, I could at least point our IT department in the right direction and perhaps use the information to fix the problem at home.

