Highlights help you identify elements before and after selection.
Pre-selection highlight
Identifies an element before you actually select it.
Hover a selectable element, then press Shift to see its highlight.
Note: With the Arrow tool active, the highlight appears without Shift.
The pre-selection highlight is especially useful to
•Pick the right one among several overlapping elements
•Label or dimension elements
•Transfer parameters among elements (see Parameter Transfer)
•Use Magic Wand
Set highlight colors
Configure highlight colors at Options > Work Environment > Selection and Element Information.
You can also turn off any or all highlights altogether.