Fix systemd service starting too early

rpi-scripts/gui/gui-start.service

@@ -9,16 +9,19 @@
 
 [Unit]
 Description=Start Python GUI for IO-control and monitoring after startup
+# note: when using After=graphical.target: it only starts after successful network connection...
 After=display-manager.service
 Wants=display-manager.service
 
 [Service]
 Environment=DISPLAY=:0
-ExecStart=/usr/bin/python3 /home/pi/git/rpi-interface-board/rpi-scripts/gui/main.py
+
+# note: some delay is needed for DISPLAY :0 to be available
+ExecStart=/bin/bash -c "/bin/sleep 6 && /usr/bin/python3 /home/pi/git/rpi-interface-board/rpi-scripts/gui/main.py"
 WorkingDirectory=/home/pi/git/rpi-interface-board/rpi-scripts/gui
 User=pi
 Group=pi
-Restart=always
+Restart=no
 
 [Install]
 WantedBy=default.target