[Geoff Bacon]

The small one is the nudge tool; it is used to tweak the position of whatever item you are working on.

Just press the close (x) on it top line and it will disappear.
You can get it back again by pressing the down arrow in the top left corner of the screen.

I usually have it enabled by default; this allows me to quickly create some annotations (not caring too much whether they are positioned correctly) and then drag them to the appropriate area. The nudge tool can then be used to tweak the final position.

When you have more than one annotation, you might want to also enable the list; this allows you to see what annotations you have created and select and/or delete them

Geoff