Stop drives expanding in folder tree, like in DO12

Hi, I've just upgraded to DO13, and can't seem to find the option to stop drives expanding in the tree, under "This PC", as I browse folders in a tab (although it only follows to 2 levels deep in the tree). I had this working in DO12, but can't see how to stop it in DO13. I have unchecked all the boxes in the Expand/Collapse section in Preferences (as I had in DO12).
Thanks,
Mark.

You may be thinking of the tree lock, if you want the tree to ignore changes in folder in the file display and act more like a list of favorites than a folder tree, similar to what File Explorer does these days.

Preferences / Folder Tree / Appearance / Show lock button

That was it, thanks. That setting didn't get carried over in the upgrade and I forgot about it!