It's a fairly good example of the kind of inconsistencies in user interfaces that confuse people. You can find this kind of thing happening in most software if you look well enough.

If you look at most of the tabs, the left side icons are usually sub-tabs. Therefore, you don't pay attention to the highlighted top left icon since it is too easy to assume it means you are on the first sub tab.

I would not have tried to click on it if I didn't have a hint about it in Mazak's screenshot above. The tooltip showed me the way.

• agiel - www.linfa.net