Welcome to B4J @Blindman. If you happen to find a good solution to your issue, hopefully you can find the time to do a write up and post it in the B4J's Tutorials section. This way we have a resource that future programmers can use/be directed towards.
This is currently not configurable. There are several IDE themes that you can select from (only one of them is dark). You can only customize the code editor colors.
I've tried all the IDE themes. With my eyesight, MetroDark is only one I can use.
Please would you consider adding another dark theme with a true black background. This would be much appreciated.
In my code editor theme .vssettings file, I had to replace all "0x02000000" with "0x00000000" to obtain a true black background in the code editor window.