Sometimes you want a (user) preference that doesnt appear in the Preferences UI.
Example: reset the Modelmanager BOM module by default.
<Preference>
<Key>BOM_MANAGER</Key>
<DefaultValue>false</DefaultValue>
<Reset>true</Reset>
</Preference>
This wil also lead to a button in the preference UI, which is not wanted.
Proposal: add a <Visible> tag to the Preference section (which defaults to true)
