OK, this time it worked under some conditions.

It works only if I opened the file without numbering first. (yes I'm dumb, but I'm ok with that

)
The first try I opened the file called Mama_Fusion_1.xcf and got this error:
Attachment:
screenshot_20230220-091615.jpg [ 99.02 KiB | Viewed 764996 times ]
It adds an "_1" to the file name it is searching for, instead of reading/opening Mama_Fusion_1.xcf, it tries to open Mama_Fusion_1
_1.xcf (2 times "_1")
Um... How to say it, I got another
horrible thought
Maybe a add function to open all file-name-[x].xcf / file-name.xcf except the one file-name-[y].xcf / file-name.xcf which is already open?
I'm almost sure that I won't be the only one to do that dumb thing

Again thank you so much Skinnyhouse