"Expand all children of this tree" It does not work properly

I have main-menu:

-Item1
--Item1-1
--Item1-2
---Item2-1
---Item2-2
---Item2-3
--Item1-3
--Item1-4

I have some menu-block.
Settings menu block:

Menu:
main-menu

Starting level:
2nd level (secondary)

Make the starting level follow the active menu item = 1

Starting level will be:
Children of active menu item

Maximum depth = 9

Expand all children of this tree
on OR off (no difference)

In my opinion:
If I choose to "off", then while on "Item-1," I need to see:

--Item1-1
--Item1-2
--Item1-3
--Item1-4

But I see:

--Item1-1
--Item1-2
---Item2-1
---Item2-2
---Item2-3
--Item1-3
--Item1-4

The same thing I see when I select "on"...In my opinion it should work differently

Also, it is not clear when it may be necessary "Maximum depth" = "Unlimited". As far as I know, the restriction sub-menu = 10. More recently I read that post here, a similar problem http://stackoverflow.com/questions/8403954/drupal-7-function-menu-tree-p...

To solve my problem I suggest a mini patch.