How do I set toolbar buttons to show its name when mousing over

[NB$4]

Some of the toolbar buttons I use are more familiar to me than others.
Previously I was able to see the name of a button when I scrolled over it
with the mouse/cursor. I'm at a new computer and these button names do not
pop up.

 

[Bob I]

Tools, Customize, Options, Show Screentips on toolbars.