At startup, Xarchiver detects the available installed archivers (tar,rar,zip etc). Since Xarchiver is a frontend (a graphic user interface to the cmd-line executables) it can't create archives whose archiver is not available. For instance if you have the free edition of rar, unrar, Xarchiver can't create rar archives since unrar allows rar archives to be opened, tested and extracted but not to be created.
Xarchiver will run in the background the cmd-line executable of the archiver with the archiver's proper switches to perform the selected operation. If something goes wrong Xarchiver reports the full output of the archiver executable in the command line output window.
Xarchiver supports drag and drop through the XDS protocol. Currently only Thunar file manager supports it. Files and directories can dragged from Thunar window to Xarchiver and vice versa. If its window is empty (no archives open) Xarchiver will prompt the user with the Figure 3.1, “New dialog” asking for the filename and the archive type to be created; after which the dragged files will be added. If the dragged file is a supported archive Xarchiver will open it instead of prompting the new dialog.