I have (had?) active columns A-N, and I used the optimal row height. Upon closing that, columns A-C were suddenly gray, and could not be edited, nor could the cursor be placed upon them, either with the mouse or with the arrow keys.
What do the gray columns mean? How did I get them gray? How can I ungray them again? Please SOMEONE answer ASAP!
Ctrl+F8 will toggle value highlighting and show the protected cells with gray background.
You can unprotect sheet.
Thank you! 
The belief that there is only one truth, and that oneself is in possession of it, is the root of all evil in the world.
— Max Born, Polish-born German physicist, 1882-1970
I believe…
but so many times I can’t grasp it.
Anyway, have you solved the problem with columns A:C?