I not understand this row "now you take your favorite droplet module and install it as a new module. both variants works in wb 2.8.3 SP4"
we have two modules with the same name and same function -> Droplets
one of them is a part of the wb-core / part of the wb2.8.3 - Package (see
Downloads)
the other one is a "private" version with a little more functionality (see
here)
on the first view in AdminTools -> Droplet you see some of the differents (icon to modify, controlbox to activate droplets etc), theses advanced functions are not avaiable in the wb-standard-droplet module
if you upgrade your wb-software, you overwrite some of the files in module/droplet-folder and now you have a mix between advanced droplet module with files from the standard module and because of that you have the error-message with the table-sorter. with this function you can change the displayed order of the droplets via drag&drop, but only in the advanced droplet module.
the file tool.php from the advanced module included the js-file and the backend_body.js use this function, but not in the standard module
both module variants are "correct", both variants works, thats way i write: choose you favorite version. if you like the version from
here, its enough, if you overwrite the files from the server with the files from the zip.
if you go the way over deinstall/new install, see my first post