If I select two archive files and execute 'delete' command, it removes both of them. But when I select two archives and execute 'extract here' command only first one is unpacked, although should be all. Availability and handling of commands 'extract into' and 'extract here' of selected not only archive files is a question (I'm not ready to give the answer).
Works fine here, probably an issue in the backend you use (xarchiver, file-roller).