The Arrow button will make your pointer back to a regular Arrow Pointer.
On the Defaults window you have the option 'Deselect tools manually after
use', when this option is checked as you select any drawing tool that will
not be unselected until you click the Arrow button, or other drawing tool.
If the 'Deselect tools manually after use' is not checked when you finish
to use a tool the pointer will return to an Arrow automatically.