Mac OS X 10.15.5 with AdoptOpenJDK 11 has black table headers

[taylor.smock]

What steps will reproduce the problem?

1. java -jar ${PATH TO JOSM JAR}
2. Open Imagery Preferences
3. See black bars

What is the expected result?

Table headers are standard greyish colour

What happens instead?

Table headers are black

Please provide any additional information below. Attach a screenshot if possible.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-05-27 21:23:59 +0200 (Wed, 27 May 2020)
Revision:16511
Build-Date:2020-05-28 01:30:47
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (16511 en) Mac OS X 10.15.5
OS Build number: Mac OS X 10.15.5 (19F96)
Memory Usage: 370 MB / 4096 MB (115 MB allocated, but free)
Java version: 11.0.7+10, AdoptOpenJDK, OpenJDK 64-Bit Server VM
Screen: Display 69734272 1280x800, Display 188945226 1920x1080, Display 188945225 1920x1080
Maximum Screen Size: 1920x1080

Last errors/warnings:
- E: Region [TMS_BLOCK_v2] : Problem loading keys for file TMS_BLOCK_v2

Notes: Only reproducible with Java 11 on Mac. Java 8/14 both work properly.