Fonts too small in alignment, annotations and Preferences and tabs not appearing correctly in Ubuntu with 4k screen

See attached screenshot provided by Marek (who demonstrated this problem).

Most text in Jalview running in Ubunut 18.04 using a Hi-DPI display appear too small (too small to read without difficulty).
This includes the alignments, the annotations, labels for both of those, a lot of text in the Preferences window (though not all -- see the "Sequence ID T..." text in the Preferences window in the screenshot).

Oddly it does not include the menus (which have taken on the themed Ubuntu font), although there is bad spacing and some appearance problems with tabs and headings (see the mostly obscured "Open new alignment" in the Preferences window in the screenshot).

Java 11 Swing is meant to be Hi-DPI display aware, but this appears to be exactly the same as the 2.11.0 installation on the same machine/monitor that uses a system JRE 1.8.

Also note that some of the widgets are themed (orange scrollbars) to the desktop. I suspect that the Ubuntu environment is interfering with the default Java LookAndFeel at least slightly!