"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" I get this message box on opening a png-image clicking with the mouse on the png-file in Dolphin. After clicking the OK-button of the message box the message box disappears and the image opens. This happens in Linux Mint 18.3 KDE 64 Live system.
*** This bug has been marked as a duplicate of bug 377880 ***