Detects print marks and sets the trim and bleed boxes to those marks.
The unit is the unit set in the PitStop Pro Preferences (Units & Guides category), for example: cm or pt
In the image below, the red marks are detected as trim marks and used to set the trim box
(blue box). The position of the vertical marks in the top and bottom left corner is
not as expected (they are not exactly on one vertical line), but the deviation (=
difference between the position of both marks) is less than the specified
threshold.