@Harmen-Jorritsma said
Bij grouping the mark colum there would be only 20 IDT_01A with the same bouding box. If the bouding box is different you will see two line with IDT_01a witf different bouding box with
@keithwilkinson
You can try the bounding box but I would not totally rely on those values but rather try to go with the door parameters as much as possible.