The print screen key does not open the screen shot tool in Kubuntu 16.10

The print screen key does not open the screen shot tool in Kubuntu 16.10.

Solution 1:

Kubuntu 16.10 replaces the old screen shot tool KSnapshot with Spectacle but does not change the keyboard setting accordingly. Under System Settings -> Shortcuts -> Custom Shortcuts the folder "Screenshots" must be developed to show an entry "Start Screenshot Tool". The trigger for this entry must be set to be the print screen key. A dialog will prompt warning that the key is already assigned; it is assigned to KSnapshot; therefore ignore the warning.

Solution 2:

This seems to have changed again in Plasma 5.20+ as per recent Fedora upgrades. The print screen key is assigned to dbus StartAgent command of Spectacle, which actually starts Spectacle in the background and shows nothing (basically useless). For a fix today you may need to reset the shortcut as per above but I think Spectacle has changed its behavior (v20.12.2 here).