Message on displayed on first run of program: "There are two actions (Cut, Delete) that want to use the same shortcut (Shift+Del). This is most probably a bug. Please report it in bugs.kde.org" This is on a fresh install of Mint 18.2 with KDE 5.8, running Gwenview 16.04.3.
*** This bug has been marked as a duplicate of bug 377880 ***