The Reset Picks button is programmed to Clear all points on screen and then reset the preview image by calling
mitk::SegWithPreviewTool::ResetPreviewContentAtTimeStep.
This works, but the cleared preview image is not reflected on the rendering windows. (If we go to a different slice and return then the preview is gone as expected)
Calling RenderingManager::GetInstance()->RequestUpdateAll() or RenderingManager::GetInstance()->ForceImmediateUpdateAll() doesn't help.