Problem with prusa i3 and "print one at a time"

[jlsilva 0]

Hello community! I'm new here and I want to talk about a problem I have with the software.

I want to print some small pieces in one at a time mode but it is impossible for me to configure it with a prusa i3 added in printers. When I add a piece in the bed, there is a very big gray square around this. I tried to set the printhead size and there is a second square that goes larger or smaller, but not the first one and I'm not able to put some of this outside the build plate (like allocating the piece in a corner). I will upload some photos to illustrate the problem, as you can see, it is unavailable to put more than 4 pieces.

When I select another printer like "prusa i3 mk2" this is not happening, there is only one gray square that you can configure in printhead settings.

Also if someone is so kind to explain me how do I need to put the exactly measures of the printhead I would thank you very much.

Sorry for my English, best regards!!

[gr5 2,172]

The new light gray and dark gray areas are set in some file. I don't know where the file is, sorry, but it's a polygon file so you can do more complicated shapes than rectangles. I'd start by finding the location of the files that define the printer.