Have you ever being frustrated by getting your project stuck after you running it and realized that you forgot to close one (or few) of your model style subvi(s) (which show front panel when called) ?
You can not do anything on your main front panel as the model vi is in front of everything and you can not stop it either! All you can do is to kill LabVIEW and re-open the project.
I believe that LabVIEW should has an option to stop anything, anywhere,anytime when you are in the development environment. This has always been an issue since I started using LabVIEW. Please add a method to the next version of LabVIEW such that developers can stop thing like this from happening.