Answer: How to make Storyline completely FULL SCREEN and BORDERLESS!
I found a solution to this long-lasting mystery!!!!
Making your .exe output FULL SCREEN with no borders:
After turning off all menu items in the PLAYER settings, go to the COLORS & EFFECTS settings and choose "Show advanced color editing". This does not look like a link, but it is.
Select all frames/borders and make them 100% transparent!
NOW, go into the loader.ini file in the root of your published output folder.
Change WindowStyle to zero: WindowStyle=0
(changed from 2 as the default)
This will get rid of the annoying border at top of screen!
You are now 100%, entirely full screen with NO BORDERS AT ALL!