file selection dialog sorting
noticed with pdfarranger, probably applies to other.
open/save as/export dialogs sorts filenames not alphabetically, but ignores some leading chars such as underscores _
while interlacing lowercase/uppercase results seems legit (although disputable, and IMHO should be an option), ignoring special chars such as _ is VERY inconvenient : naming files and dirs with such a prefix is usually done for a reason, namely so they always appear at the beginning or end of the list.