If you right click on a scenario, you have 4 rendering options, some are outdated/unused. Remove outdated/unused rendering options - Render in 2D (SWT), Render in 2D (which uses MapPaneBuilder that is not double buffered).

Also, "Render in 2D - Swing" should follow the naming convention the other options use, e.g. Render in 2D (Swing)