[GREENFOOT-663] Switch MessageDialog to JavaFX
The Greenfoot API version check now takes place on the server VM, which is correct. However, it calls through to GreenfootMain.updateApi (which itself we may want to move, as that is usually for debug VM code, not server VM), which creates MessageDialog, which is Swing-based. We should either port MessageDialog to JavaFX, or find another existing JavaFX class to use instead for showing this dialog.
- Issue type: Task
- Priority: Medium