Why do boxes and options appear selected with a blue highlight?

Disable "Enable Full Keyboard Access" in System Preferences > Accessibility > Keyboard > Navigation.

That is not his request ,nor mine. Get rid of not change color.. Why did it show up to begin with? Did we hit a combination of keys. I also cannot get the space bar to work when anything is highlighted with the blue box. I am going to call Apple Support and hope I get someone knowledgeable.

Ok, I see what you mean.

I cannot reproduce it, even with keyboard navigation turned on in System Preferences->Keyboard->Shortcuts.

If you get your answer, please share, for the benefit of the OP and others.

You can choose a different highlight color, in System Preferences->General, but otherwise this is perfectly normal.

EDIT: make that "accent color"

I am having the same issue but with my IPad Air Gen. 4 and it’s magic keyboard. No matter what I do it wont go away and the space bar stops working on the keyboard as well,please help.