How to detect if Visual studio IDE is being closed

Good evening,

In my project, I'm starting Visual Studio 2015 as follows:

Type type = Type.GetTypeFromProgID("VisualStudio.DTE.14.0");
dte = (EnvDTE80.DTE2)Activator.CreateInstance(type);
dte.MainWindow.Visible = true; 
dte.Solution.Open(UserPreferences.Instance.ProjectSlnFilePath);

I've noticed that when I close the IDE, a Visual Studio background process starts running for some reason. I'm looking for a way to detect when the IDE is being closed, in order to somehow kill or avoid that background process from being created. I tried to do the following, based on this thread:

dte.Events.DTEEvents.OnBeginShutdown += DTEEvents_OnBeginShutdown;

But it doesn't trigger. I've tried other events, such as Window_Closing and so on, but for what it's worth, the only events I got working so far are Events.WindowsEvents.WindowActivated and Events.SolutionsEvents.Opened.

Any ideas? Thanks!