Local Overrides Sample: Disable the Idle Timeout - bp2008/ui3 GitHub Wiki
This script will change the default timeout to 0 every time UI3 loads, effectively disabling the timeout for all users.
To learn more about ui3-local-overrides, see: Local Overrides Scripts and Styles
ui3-local-overrides.js
OverrideDefaultSetting("ui3_timeout", "0", true, true, 1);