Try clicking another point on a corner of the shape. Notice that when you select the new point,
the previous point is deselected.
Revert to the last saved version of the file by choosing File > Revert. In the dialog box that
appears, click Revert.
Changing the size of anchor points, handles, and
bounding box display
The anchor points, handles, and bounding box points may be difficult to see at times. In
the Illustrator preferences, you can adjust the size of those features. By choosing
Illustrator CC > Preferences > Selection & Anchor Display (macOS) or Edit >
Preferences > Selection & Anchor Display (Windows), you can drag the Size slider to
change the size.