I like using Ubuntu desktop when doing development work but I find that the default screen lock timeout settings can be a bit annoying.
If you want to extend the amount of time your screen is inactive before it times out then this is how you do it.
- In the top right of your desktop click the icon and select System Settings.
- In the settings select Brightness & Lock
- In here, change the setting to whatever is appropriate for you then click the x in the top left.
- That should be it. Let me know if this worked for you or not.