Activator C++ code does not fire on clicking notification.

I've done the following things
* Manually copied InteractiveNotifications.dll to resolve a runtime error
* Fixed up calls to v8::String::Value compile error in notification_bindings.cc
* Manually updated CLSID in two places in InteractiveNotifications.cpp to the correct value
* Verified I have the correct CLSID by running [lnk-parser](https://code.google.com/archive/p/lnk-parser/) on my Squirrel-generated shortcut.
* Called `registerComServer()` and `registerActivator()` during startup.
* Verified that a registry key is created under `Computer\HKEY_CURRENT_USER\Software\Classes\CLSID\{d52b1d2e-f9cd-56b2-bd84-21a832557d71}` - LocalServer32 has a default value of `C:\Users\me\AppData\Local\MyApp\app-1.0.0\MyApp.exe`
* Send a notification via NodeRT `ToastNotification`, using the exact template from the readme, and sent after the registration. The notification shows just fine.
* I've set up my app to accept protocol activations and enforce single-instance and validated that it's working by invoking from Start -> Run. (But I don't think it's making it that far)

But nothing happens when I hit the button. It hasn't worked in any other combination, like with a standalone button either. It doesn't seem to work at all when I specify `activationType="foreground"` so I've left it at `activationType="background"`.

I dug into the code and can see that the `Activate` method in InteractiveNotifications.cpp is set up to handle the notification activation and launch the protocol URI with `ShellExecuteW`. I put some code at the top of the function to write a log message to a file, but the file is never written. So I don't think it's making it inside that method at all.

What else can I check here? Are there any debug logs for notification activations? Have I missed something?