My config is set so that double click on a lister background takes me up a level. Recently I found myself going up unexpectedly when browsing my way through image folders. After a bit of research I discovered that it happens when I do a "lazy" double click on a thumbnail which is only partially shown at the bottom of the lister. The partially displayed thumbnail is auto relocated to become fully visible and the second half of my double click ends up with the cursor in the space between thumbnail rows.
I can see the sense of adjusting the selected thumbnail position so the whole thing is visible and now that I know about it, I'll be more careful with my double clicks. My question is.. has it always been this way or is this a recent change to the UI? I often work with folders in thumbnail mode and don't recall this happening until recently.
Maybe it's just my ageing reflexes slowing my double clicks to a crawl..... 
Regards, AB