The screen is black if I debug the GUI directly. I think B4J inside Wine is using Windows version of OpenJDK.
I use B4J-bridge and connected to same IP. The window is not black. I think using this way, the IDE is now using the Linux OpenJDK.
I tried to install B4J on a new Linux distro yesterday. Using Wine and inside VirtualBox.
The latest version 1.4.2 has removed X11 and B4J (or JavaFX) is not running correctly under Wine.
I reinstalled version 1.3.9 and login into Xorg session and B4J is running much better.