Salvo I tested a new SploinerGUI version that papio sent me to test, now SploinerGUI works fine with add files, but I found a small problem that papio will see to fix, otherwise it will be reported in the readme.
If, for example, the chopped chunks of a ZIP file, with extension name 000, 001, 002 etc.., if you rename them 00, 01, 02 etc... the resulting archive file will be missing a letter, which can also be in the extension, and the archive will be corrupted
Of course it is not a problem if the broken files are created by Sploiner, but if maybe you have to merge bits of files downloaded from the Web with those names they will not be able to be merged.
I am also creating the icons for all platforms.