Adding file(s) to archive blocks from (re)using DO lister

I am using 7-zip as default archiver. Let's say I have .7z archive file which I want to update. Now I open .7z archive and want to put some new file in archive. If I do that, I cannot use anymore that lister. I minimize .7zip archive in background but still cannot use that lister until job is finished. Only solution is to open new lister from DO tray icon. Where is here multithreading/multitasking?