JabRef 5.0-beta.362--2020-01-25--ac90ad2
Linux 5.4.13-3-manjaro amd64
Java 13.0.2

• I have tested the latest development version from http://builds.jabref.org/master/ and the problem persists

• I have built the latest master branch from source (commit ac90ad2) and also observed this issue in the current beta release.

Steps to reproduce the behavior:

1. Click on any item in the menu bar (File, Edit, Library, Quality, Tools, View, Options or Help), above the text line (anywhere in the orange area in the image below, colors were added by me to help explain the problem).
2. Try to select anything from the submenu that opens.

Expected behavior:

• The corresponding submenu should stay open after clicking in its title.

Actual behavior:

• If the user clicks the top half of the menu bar (orange area in the image), the submenu that opens closes immediately after the left mouse button is let go of. If you maintain the left mouse button pressed, the menu stays open, but nothing can be selected while the left mouse button stays pressed.
• If the submenu is clicked in its bottom half (blue area in the image), everything works as expected.