fixed small bug in adding the overhang in multiple times

insert.py

@@ -113,9 +113,9 @@ class ShelfInsert(Boxes):
             return 0
 
     def xSlots(self):
-        posx = -0.5 * self.thickness
+        posx = -0.5 * self.thickness + self.Overhang_front_overhang
         for x in self.sx[:-1]:
-            posx += x + self.thickness + self.Overhang_front_overhang
+            posx += x + self.thickness 
             posy = 0
             for y in self.sy:
                 self.fingerHolesAt(posx, posy, y)