Fix: Avoid overflow

Ensure set_play_state is called even when time_histogram_per_timeline is None.
The previous fix incorrectly skipped setting play state flags (playing/following)
when no histogram data was available, which could cause incorrect UI state.

Author: joelreymont

crates/viewer/re_viewer_context/src/time_control.rs

@@ -529,23 +529,31 @@ impl TimeControl {
 
         if let Some(new_play_state) = blueprint_ctx.play_state()
             && new_play_state != self.play_state()
-            && let Some(time_histogram_per_timeline) = time_histogram_per_timeline
         {
-            self.set_play_state(time_histogram_per_timeline, new_play_state, Some(blueprint_ctx));
+            if let Some(time_histogram_per_timeline) = time_histogram_per_timeline {
+                self.set_play_state(time_histogram_per_timeline, new_play_state, Some(blueprint_ctx));
+            } else {
+                // Even without histogram data, we need to set the play state flags
+                let empty_histogram = TimeHistogramPerTimeline::default();
+                self.set_play_state(&empty_histogram, new_play_state, Some(blueprint_ctx));
+            }
         }
 
         if let Some(new_loop_mode) = blueprint_ctx.loop_mode() {
             self.loop_mode = new_loop_mode;
 
             if self.loop_mode != LoopMode::Off {
-                if self.play_state() == PlayState::Following
-                    && let Some(time_histogram_per_timeline) = time_histogram_per_timeline
-                {
-                    self.set_play_state(
-                        time_histogram_per_timeline,
-                        PlayState::Playing,
-                        Some(blueprint_ctx),
-                    );
+                if self.play_state() == PlayState::Following {
+                    if let Some(time_histogram_per_timeline) = time_histogram_per_timeline {
+                        self.set_play_state(
+                            time_histogram_per_timeline,
+                            PlayState::Playing,
+                            Some(blueprint_ctx),
+                        );
+                    } else {
+                        let empty_histogram = TimeHistogramPerTimeline::default();
+                        self.set_play_state(&empty_histogram, PlayState::Playing, Some(blueprint_ctx));
+                    }
                 }
 
                 // It makes no sense with looping and follow.