100% Activity on Firefox when editing a file

[EricGlaenzer]

That's really interesting, when I edit a buster config file, Firefox activity on OSX skyrockets to 100% and stays that way until I close the tab. Editing any other files doesn't have any problem. Here is the content of the buster config file:
var config = module.exports;

config["Browser tests"] = {
rootPath: "../",
tests: ["test/browser/*/.js"],
extensions: [require('buster-selenium')],
'buster-selenium': {
// required, can be either selenium-webdriver or wd
driver: 'selenium-webdriver'
}
};

And I saved it under myApp/Test/buster.js