are there any ways to set firefox's proxy settings? I found here information about FoxyProxy but when Selenium works, plugins are unactivated in window.
Look at the documentation page.
Tweaking an existing Firefox profile
You need to change "network.proxy.http" & "network.proxy.http_port" profile settings.
FirefoxProfile profile = new FirefoxProfile();
profile.addAdditionalPreference("network.proxy.http", "localhost");
profile.addAdditionalPreference("network.proxy.http_port", "3128");
WebDriver driver = new FirefoxDriver(profile);