Unclear functions in Subsurface UI

[Willem Ferguson]

I am updating the material for the user manual. Here are a few things I 
struggle to understand about the UI:

1) Export HTML Word Map on File item of main menu. This generates an 
HTML world map with no information superimposed on it. Is this function 
fully operational yet? I cannot see the purpose of this option??

2) The Preferences Units panel, the checkbox at the bottom 'Show units 
in text labels'. This does not appear to produce any noticeable effect 
in any of the panels. What does this option do?

3) The Preferences Graph panel, the checkbox 'unused cylinders'. What 
about unused cylinders? What does this do?

Kind regards,
willemf