is there a way to configure web messenger to disconnect interactions if the user closes their browser or the chat window?

Hey Nicole, 

Not as current - though I have implemented an app/plugin that helps when a customer is no longer there. Part of this app will understand when a message is sent to a customer when they are no longer there, send a pre-defined message and then disconnect the web message automatically sending the agent into ACW. We have seen a significant uplift in reductions to AHT and overall availability to other customers by using this. This is a bit of a shameless plug though - as I have built this. 

Let me know if you would like some more info would be happy to set up a call.