What is the magnifier?
When you attempt to select a target by touching the screen and there are multiple targets in the vicinity of your touch, the magnifier appears. It zooms in on the area around your touch point to give you the opportunity to select the correct target.
If there are still too many targets, touching again will zoom in more. This will repeat until you select a target or dismiss the magnifier.
To dismiss the magnifier, just touch somewhere outside of it.