JabRef 5.0-dev--snapshot--2018-09-09--master--4c7194a39
Linux 4.17.19-200.fc28.x86_64 amd64
Java 1.8.0_172

1. I used web search and found & imported item. works.
2. I enter a search term in the top search field to search my entry table.
3. I press enter - and then the web search is activated, rather than the table search.