I have JabRef 5.0 installed in a Windows 10 machine. It works remarkably well, but there appears to be an annoying problem with the "Show/Edit Bibtex Source" pane. From time to time, it just gets stuck, not allowing me to write or edit any entry at all. If I restart JabRef, this pane starts working OK again, but after a while, it gets stuck again.

I will give you an example. I went to Google Scholar and just copied the following BibTex citation:

@book{cournot1995mathematical,
title={Mathematical principles of the theory of wealth},
author={Cournot, Antoine Augustin and Fisher, Irving},
volume={1},
year={1995},
publisher={James & Gordon}
}

Then go to JabRef, choose "New entry", then in the "Select entry type" I choose "Book", and a new pane opens up with the single entry:

"@book{,
}"

I try to paste the BibTeX citation above on top of this, but JabRef does not allow me to do anything at all. This pane/window is stuck. Indeed, I can manually copy the entire citation into the "Required fields" which keeps going properly, but this is a not very useful approach for at least three reasons: (i) is not very efficient, (ii) is prone to typing mistakes, (iii) if I want to add a new column to the entries of this citation, I will not be able to do so.

In some other times, JabRef allows me to copy the citation into the "Show/Edit Bibtex Source" pane, but does not allow me to change anything in the entries of this citation. It gets stuck again.

Once again, if I restart JabRef everything works perfectly for sometime, but then the same problem keeps coming back.

JabRef is a magic piece of software. This small bug is just annoying.