Playlist mode, as the video / audio players. Opening after the end of the book the next file from a prepared list, instead of a file in the folder. Enough even a simple playlist from the list by drag & drop, or even just to move to the next file from favorites (but it would be a separate playlist and bookmarks).
It would be nice if there were marked as readed.
By the way the numbering would be good to bookmarks.
If you open more than one file at once, either by passing more command line arguments to MComix, or by selecting more than one file from the "Open" dialog, only the selected files will be read, and all other files in the same directory will be ignored.
Same thing applies for files in the library, by the way.
This is certainly good, but this in no way replaces the playlist.....
Have you tried PyComicsViewer?
https://sourceforge.net/projects/pycomicsviewer/
It has some interesting file browsing functionality.
See the file tab in the screenshots https://sourceforge.net/dbimage.php?id=306435
"By the way the numbering would be good to bookmarks."
I'm not sure what you mean, could you please explain?
I do not remember trying it or not, but at least saw.
I need not lose a large number of new chapters / volumes are now using for this bookmarks (Library dialog for 3 years and I do not like it ....).
Show number of each bookmark in the Edit Bookmarks dialog.