Open New Instance on Project load prompts user again.

[dsjove]

Description of the bug

I understand PrusaSlicer is architected to be a single-document app. This is very frustrating as a Mac user where I expect an application to be able to support 0 to N documents; not 1 and only 1! The whole concept of allow and open new instance hurts my head. I would love it if that whole concept goes away.

Bug -

Sometimes The 'Load project File' option to open new instance puts the user in a weird state because the new instance immediately prompts the same thing with "open new instance" pre-selected. Sometimes I am not even prompted and the 3MF files are merged.

Project file & How to reproduce

All file opens were started from the file system UI. I could not tell you how to get into those bad states.
The screenshot sows both an unexpected merge and an unexpected recursive "open new instance".

Checklist of files included above

• Project file
• Screenshot

Version of PrusaSlicer

Latest

Operating system

Mac, Latest

Printer model

XL with latest firmware