I’ve also has some very strange behaviour from MEW with lots of files open. The tabs with the filenames on them were going about half way down the screen, so around 200 or 255 files sounds about right. There was something that Mew just refused to do (I think Mew aborted), but I can’t remember what – it may well have been running a compiler. After reloading Mew, I had to close some of the files to make it work properly again. So I agree, Mew has a limit of somewhere around 255 files.