Updates to one item are recieved by subscribers to other items

I have a browser with multiple tabs open, each subscribed to a different item. I am seeing a strange problem whereby an update to one item [eg eventListener.Update("uniqueId", dataDictionary, false) ] is displaying in every browser window, even if that window is not subscribed to the item. I'm guessing this is due to something I've mis-implemented in the .Net adaptor, but I know I am sending out the right Ids when I call Update.

Does anyone have any thoughts about what else it could be?

Thanks
Craig

As you, supposedly, refer to a demo application,
the simplest way to proceed is by looking at the Server log.
In the log, you can find the subscription requests issued by the various tabs and check whether they are as expected.

If no issues appear, you could also follow the update flow in the log, after setting the priority of the LightstreamerLogger.subscriptions and LightstreamerLogger.pump categories to DEBUG in the Server log configuration file.