I too have only just seen your query.  I know FE is sometimes unstable. It has to be nursed along.  I only ever have one window open - the one I am working on.  If I see anything that looks good I simply save it in a folder in my current month's images.  Quite often if you ctrl alt delete and open the task manager you may find you are running a couple of FE's as one has not shut down properly.  Simply delete one. It works for me. A brilliant thing about FE is that if it does go haywire, it will save the last image you were working on. Just be gentle and all should be well.
If you are working with ten windows open FE is performing fine:-)