Always poll after the first frame has been rendered

This ensures that subsequent frames are rendred if needed

src/window/update_loop.rs

@@ -98,8 +98,11 @@ impl UpdateLoop {
         .max(1.0);
 
         let expected_frame_duration = Duration::from_secs_f32(1.0 / refresh_rate);
-        if self.should_render == ShouldRender::Immediately && !vsync.uses_winit_throttling() {
+        if self.should_render == ShouldRender::Immediately && !vsync.uses_winit_throttling()
+            || self.num_consecutive_rendered == 1
+        {
             // Only poll when using native vsync
+            // NOTE: Also after the first frame after an idle period has been rendered
             (Duration::from_nanos(0), Instant::now())
         } else {
             let mut deadline = self.previous_frame_start + expected_frame_duration;