Single click to open not working in Dolphin

Problem

I recently upgraded a Kubuntu 15.10 operating system to Kubuntu 16.04. I used to use single-click to open files and directories in the Dolphin file manager. This stopped working after the upgrade. Only double-click would open files and directories.

Solution

• The option to choose between single-click or double-click can be set in System Settings → Input Devices → Mouse. However, this had no effect in Dolphin. I even checked that it was set:

$ cat ~/.config/kdeglobals | grep SingleClick
SingleClick=true

• Further investigation showed that this was a known bug. It is fixed, but I guess it will be a while before that flows downstream to Kubuntu.

• The only solution that worked for me was to install the older Dolphin from KDE 4 and running it instead of the default Dolphin from KDE 5:

$ sudo apt install dolphin4
$ dolphin4