In other Desktop Environments under linux if using any app which uses KIO (such as Krusader, Dolphin) the application does not display any kind of progress dialog while working, unless kuiserver is installed too. This is a problem, because currently there is no way to build a standalone kuiserver from the plasma-workspace package without having to build other, sometimes conflicting dependencies. For example I am currently using connman to manage my network connections and plasma-workspace needs networkmanager as a hard dependency. The original bug was opened against kuiserver (plasma-workspace): https://bugs.kde.org/show_bug.cgi?id=381667
Bug 381667 was already moved to frameworks-kio.