Running script with startup applications

I have created a script that opens Firefox and makes it full-screen. When i use startup applications to run my script i doesn't start after reboot, but works perfectly if i just run it from the desktop.

My script start.sh

#!/bin/bash
sleep10
firefox -url http://URL.com &
sleep 10
xdotool key F11
xdotool movemouse 10000 10000

The script i located in the desktop folder and have permissions 777 and Allow executing file as program is ticked.

Startup Application settings

Name: Astartscript
Command: scriptpath/start.sh (Used browse to locate the script)

What am i doing wrong?

Try adding a display to it: DISPLAY=:0.0 firefox... startup application is probably triggering this in the background and there's no display active yet.

Note: I've not tested this, but it's probably the first thing I would try

Also, I would probably remove the first sleep, as that often causes issues when auto-running things... Latest MATE has a delay option built in (although now that I think of it, it's probably not shipped with Ubuntu yet)