Expand some subitems (I've only tried this with TLIs and their children), then scroll down so that some of the children of a parent disappear at the top while some 'younger' children of that parent are still visible at the very top of the grid view. Then click to select one of those still visible children and press Ctrl-Left to collapse the branch. Now the tree will not be collapsed until you cursor up or Ctrl + cursor up or the mouse wheel to scroll up until the parent item is moved back into the visible area.

 

Cheers