Protractor tests run in parallel influence each other

Question

I currently have Protractor set up to run multiple Chrome instances so that I can run my tests in parallel. However, I've noticed that the tests in one browser instance are influencing tests in another browser instance. For example, if I have one test that opens a drop-down menu, I see the drop-down menu open in the other browser instances, even though that has nothing to do with the other tests. Why would this occur? Can someone provide assistance for how I can run tests in parallel in isolation?

conf:

 'use strict';

exports.config = {
  baseUrl: 'http://localhost:8080/',

  specs: [
    './tests/**/*.spec.js'
  ],

  exclude: [],

  suites: {
    testsA: './tests/tests-a/*.spec.js',
    testsB: './tests/testsB/*.spec.js',
    testsC: './tests/testsC/*.spec.js'
  },

  framework: 'jasmine2',

  allScriptsTimeout: 110000,

  jasmineNodeOpts: {
    showTiming: true,
    showColors: true,
    isVerbose: false,
    includeStackTrace: false,
    defaultTimeoutInterval: 400000
  },

  directConnect: true,

  capabilities: {
    browserName: 'chrome',
    shardTestFiles: 'true',
    maxInstances: 5
  },

  onPrepare: function () {
    let SpecReporter = require('jasmine-spec-reporter');
    // add jasmine spec reporter
    jasmine.getEnv().addReporter(new SpecReporter({displayStacktrace: true}));

    browser.ignoreSynchronization = false;
    require('babel-core/register')({ 'presets': [ 'es2015' ] });
  },

  /**
   * Angular 2 configuration
   *
   * useAllAngular2AppRoots: tells Protractor to wait for any angular2 apps on the page instead of just the one matching
   * `rootEl`
   *
   */
  useAllAngular2AppRoots: true
};

Answer 1

This turned out to be a problem with the Browsersync settings in webpack config, not with browser instances. Setting ghostMode:false in the Browsersync settings section of the webpack config solved the problem

Answer 2

This has to do with how your app is written. In an ideal situation this should not happen because each browser instance is a separate session. This could be solved by using Selenium grid and running each browser on different VM.