message: Fix glow and multiple windows usage
  The context might not be current at redraw
diff: @@ -146,7 +146,7 @@ async fn run_instance<A, E, C>(
  mut runtime: Runtime<E, Proxy<A::Message>, A::Message>,
  mut debug: Debug,
  mut receiver: mpsc::UnboundedReceiver<glutin::event::Event<'_, A::Message>>,
  - context: glutin::ContextWrapper<glutin::PossiblyCurrent, Window>,
  + mut context: glutin::ContextWrapper<glutin::PossiblyCurrent, Window>,
  exit_on_close_request: bool,
  ) where
  A: Application + 'static,
  @@ -255,6 +255,16 @@ async fn run_instance<A, E, C>(
  }
  event::Event::RedrawRequested(_) => {
  debug.render_started();
  +
  + #[allow(unsafe_code)]
  + unsafe {
  + if !context.is_current() {
  + context = context
  + .make_current()
  + .expect("Make OpenGL context current");
  + }
  + }
  +
  let current_viewport_version = state.viewport_version();
  if viewport_version != current_viewport_version {
  