Raivo Laanemets. Software consultant.

KDE's KDialog hangs if a remote share (NFS for example) server connection is down. All applications using the native file open dialogs will become useless for opening files. This includes text editors such as KWrite and Kate. This issue is especially bad in the case of an emergency when the network goes down and you need to edit conf files to debug or reconfigure it. This is a well-known issue and reported long time ago. However, there are no known workarounds, just pray that the network never goes down, or just use a terminal-based editor (like nano) to edit files.