I thought, you might be interested in the output of the new instance launched with another instance being open, the relevant lines are
WARNING **: Error while sending message: GDBus.Error:org.freedesktop.DBus.Error.NoReply: Message did not receive a reply (timeout by message bus) at /usr/bin/shutter line 320, <DATA> line 19.
INFO: There is already another instance of Shutter running!
Also, the problem is not related to the PrintScreen shortcut, it appears also when both instances are launched from the terminal via "/usr/bin/shutter --full".
I thought, you might be interested in the output of the new instance launched with another instance being open, the relevant lines are
WARNING **: Error while sending message: GDBus.Error: org.freedesktop .DBus.Error. NoReply: Message did not receive a reply (timeout by message bus) at /usr/bin/shutter line 320, <DATA> line 19.
INFO: There is already another instance of Shutter running!
Also, the problem is not related to the PrintScreen shortcut, it appears also when both instances are launched from the terminal via "/usr/bin/shutter --full".