in Settings -> Navigation, the Mouse options are missing - appear to have been there in 15.04.0 see discussion https://forum.kde.org/viewtopic.php?f=223&t=128669 Reproducible: Always
Thanks for the bug report! > in Settings -> Navigation, the Mouse options are missing Please use the mouse kcm instead. Single/double click is a setting with global effects, so this should only be changed in System Settings (not in an application).
*** Bug 361138 has been marked as a duplicate of this bug. ***
*** Bug 363746 has been marked as a duplicate of this bug. ***