Fixed the warning about unsaved changes appearing only by chance (#1050)

app/MindWork AI Studio/Tools/MessageBus.cs

@@ -208,19 +208,42 @@ public sealed class MessageBus
         return messages;
     }
     
+    /// <summary>
+    /// Asks the receivers a question and returns the first answer.
+    /// </summary>
+    /// <remarks>
+    /// Every receiver which never narrowed down its events gets the question as well, but only the ones
+    /// which handle it answer. All others return MessageBusAnswer.NONE and are passed over, cf. the remarks
+    /// on MessageBusAnswer for why a bare result cannot express that.
+    /// <br/><br/>
+    /// A question stays within the circuit, i.e., the window, of the sender. The app keeps the circuits of
+    /// reloaded windows around for a long time, cf. the retention settings in Program.cs, and their components
+    /// are still registered: the chat of such an old window must not answer for the one the user is looking
+    /// at. Receivers without a circuit, such as hosted services, serve every window, and a sender without a
+    /// circuit asks all receivers.
+    /// </remarks>
+    /// <param name="sendingComponent">That's you, the sender.</param>
+    /// <param name="triggeredEvent">The question to ask.</param>
+    /// <param name="data">What the question needs to be answered, if anything.</param>
+    /// <returns>The first answer, or the default of TResult when no receiver answers. Asking for unsaved
+    /// changes thus yields false when no chat is open.</returns>
     public async Task<TResult?> SendMessageUseFirstResult<TPayload, TResult>(ComponentBase? sendingComponent, Event triggeredEvent, TPayload? data = default)
     {
+        var senderCircuit = sendingComponent is IMessageBusReceiver sender && this.receiverCircuits.TryGetValue(sender, out var circuitState) ? circuitState : null;
         foreach (var (receiver, componentFilter) in this.componentFilters)
         {
             if (componentFilter.Length > 0 && sendingComponent is not null && !componentFilter.Contains(sendingComponent))
                 continue;
 
+            if (senderCircuit is not null && this.receiverCircuits.TryGetValue(receiver, out var receiverCircuit) && !ReferenceEquals(receiverCircuit, senderCircuit))
+                continue;
+
             var eventFilter = this.componentEvents[receiver];
             if (eventFilter.Length == 0 || eventFilter.Contains(triggeredEvent))
             {
-                var result = await receiver.ProcessMessageWithResult<TPayload, TResult>(sendingComponent, triggeredEvent, data);
-                if (result is not null)
-                    return (TResult) result;
+                var answer = await receiver.ProcessMessageWithResult<TPayload, TResult>(sendingComponent, triggeredEvent, data);
+                if (answer.IsAnswered)
+                    return answer.Value;
             }
         }