I defer to BBill's explanation above, but will add the point that in the new library tree it is very easy to no longer be where you think you are, even though the folders and items in the tree view have not changed. In the old library, you could only see the contents of one folder at a time, so you knew where your save would take place. It couldn't be anywhere else.

It's true that in P8 you can save to a folder other than the one you THINK you're in, but I maintain you can also save to nowhere at all. That is, somehow the folder has become de-selected, yet you can still click on the + button and name the saved item as if it is really being saved. This is true on Mac, anyway. I have saved items and not been able to find them anywhere in my runtime. If I actively re-select the folder and save again, this time it will show up there (sometimes not instantly, but if I go out and back in again to check).

That's what I mean when I say P8 forgets where you are in the library even if you have done nothing to change location. It needs the folder to be selected again. This is not consistent behavior in my case.

I think there may be a memory leak, because sometimes most or all of the menu items will be grayed out and the shortcuts stop working until a relaunch of P8. I don't know if this could affect library behavior.