So i dont know what option i may have clicked and i've spent some time looking for it.
When i open Lister, (i always run dual vert) it is fine, everything works but when i click the close X the top right one, not the individual Lister X's the right Lister closes which then becomes a single Lister view, then i click the top right X again and then the whole Lister closes, I have never seen this before. It has always been click the top X and the whole thing closes at once, never 2 clicks to make a lister close.