LocatorRegion

LocatorRegion
is an option for Locator that specifies where the locator object should by default be allowed to go when it is dragged.

	Automatic	the plot range of the current graphic
	Full	the full image size of the current graphic

LocatorRegion->Full does not allow a locator object to go into space left as a result of a mismatch between settings for AspectRatio and ImageSize.

LocatorRegion affects only interactive manipulation of locator objects, not resetting through Dynamic.

Specify whether the Locator should stay within the PlotRange of current graphics:

Out[1]=