How to tell if a FORM was launched with FSAL or a Browser

We've incorporated into our applications to launch a specific close.htm upon exit. This has the effect of closing the blank browser left behind when the form / application was launched.

Now when we run via FSAL and exit, we see the flash of what appears to be the browser and the close.htm OR it makes the browser focus come to the forefront.

I'm wondering if I can determine the launch source for the application - and if it was a browser - I can use the close.htm upon exiting. Whereas if FSAL launched the form / application I wouldn't need to do that.