JabRef version JabRef 5.0-dev--snapshot--2018-11-07--master--144522d61
on Windows 10 10.0 amd64
Java 1.8.0_181

Steps to reproduce the behavior:

1. Open a literature database
2. Use search field above entry list e.g. for searching an author name
3. Double-click on one of the found entries to open its edit section
4. Click on the 'x' at the right side of the search field in order to empty it and type a new search string

When I do that, shortly after step 4 the focus is suddenly put onto the Author field of the edit section instead of the search field. If I do not care, I am then overwriting the author information with my new search string.

Edit: There seem a few similar issues already posted in this list, however they are from 2016 and clearly do not address the newest developer snapshot.