The Magnify Tools allows you to zoom in or out of the level being edited. This allows you to fine tune positions of objects if they require it.
Magnify will zoom a level from 1X to a Maximum of 4X in steps of .5X (ie.. 1X, 1.5X, 2X, 2.5X etc..)
When you first start editing a level. This zoom will default to 1X as pictured below.
The current Zoom level is displayed on the Status bar at the bottom of the editor window.
Clicking on the Magnify icon will change the current cursor to a Magnifying Glass. (as pictured below).
Left Clicking on the Mouse will Zoom into the level using the magnifying glass as the center of the zoom. Right Clicking on the Mouse will Zoom out.
The Maximum Zoom is 4X