I just, uh, exploded the grid screen
By just fooling around with a little setting
Now that was funky...
On the grid settings page, I clicked the small light gray cog on the top right of the grid.
Then it gave me the possibility of adjusting the grid size.
Just for kicks, I chose maximum... 24x9.
What happened?
The actual window grew gigantic and out of the bounds of the display. With part visible of course.
Then when I managed to bring it back with some magic (the part with the cog, to click it again), I adjusted back to 3x3...
... and now it fully disappeared.
Fun, but, not fun...