Objects are highlighted when the pickbox cursor rolls over them, providing a preview of which object will be selected when you click. Pretty cool stuff. You do have some options related to how this function works, or you can even turn it off.
In the Options dialog box under Selection is the following new area.
You can set it so that highlighting of objects is done only when a command is active or not. Seems like they could have handled this with one check box, but I am not the programmer so what do I know.
The Visual Effects Settings button does even more.
The first area is where you set up the visual response to your selection. You can select Dashing or Thicken (my choice below) or Both.
The Advanced button give you even more choices. Like excluding objects on Locked layers and various other things.
The next section of the dialog box is for window and crossing selections.
When you specify an area to select multiple objects, the background of the area becomes transparent and colored.
These selection previewing effects are turned on by default. You can turn them off or change the appearance of selection previewing . When the PICKBOX system variable is set to 0, selection previewing of objects is not available.
You can adjust the colors and the transparency value also. I made mine a little more transparent.