Unfortunately $msfile suffers from the >900-char limitation. "Too many" in $msfile means "when the lengths of the selected file names added together (without the path) and then added to the length of the folder name exceed ~980 chars".
This makes $msfile almost unusable. And it's a shame because there is already $msfile(N); one would think that the >900-char limitation would not apply here since we're accessing each file separately (they aren't all dumped in a single string).
