JabRef version 3.8.1 on Debian GNU/Linux stretch/sid with JRE OpenJDK 1.8.0_111 and Xfce 4.12.

Description after performing a search and cleaning the search field, switching to another tab and back will reinsert the search query.

Steps to reproduce

1. Create two empty databases (they need not be empty, but this seems the easiest path to reproduce the error);
2. Press CTRL+F and search for anything on the first database;
3. Erase the contents of the search field (either by deleting, pressing ESC or clicking on the X button);
4. Switch to the second database;
5. Switch back to the first database.

Expected behavior: the first database should be displayed normally and the search field is empty;
Actual behavior: the first database shows the results of the search and the search field contains the deleted query terms.