Files with names including Unicode characters > 256 cannot be attached to transactions

BillG2

I have a receipt image pdf file whose name includes Unicode characters 277, 275 and 239. I cannot attach that file to a transaction using drag and drop or by choosing the file using Add file. If I change the three characters to Unicode Basic Latin characters, attaching the file works just fine. Please add support for valid Windows file names with these Unicode Latin Extended-A characters.