Blackness covering certain areas

I am getting problems with a module in Vassal whereby parts of the GUI become in black. I can remove the black by dragging over it but it is annoying and makes it difficult to play.

Any ideas what is causing it?

Thanks.

Here is a screenshot.

You’ll have to provide a lot more information. What operating system? What version of Java? If on a PC, do you have video drivers up to date?

Hi

I am running Windows 10 with latest version of Java.