I tested the issue, and Make arangement did not solve it. The problem still exists.
OK, then I'm going to need explicit steps (renaming examples), everything needed to reproduce the problem on my end. Perhaps screen shots of the contact sheet before arranging, after arranging, and after switching back to PM.
-Kirk
Strange! My first test intended to fully document has failed. It may be bacause I only used english names no ancient characters.
Then I started off with another set of images. I first renamed them to {seqn} 1-16.
Then aranged them in my desired order, then I wrote this part of this text and I switched back to PM.
I renamed the images adding some description into the filenames (in my native language - this part might be the problem with ancient characters?).
I switched back to the web browser to continue this text, and switch back to PM to see it disrupst the sort again.