This section provides information and instructions on a few features that are known to be difficult to use or need modification to work.
Mozilla Firefox changed important APIs in version 48 that affected their compatibility with WebDriver which directly affects TestBench. Firefox 48 and posterior versions will require the use of GeckoDriver that is not feature complete or fully compatible with Selenium currently. As a workaround it is recommended to use either Firefox 47 or Firefox ESR (currently at 45.3) to execute tests on Firefox until this can be fixed with a stable release of GeckoDriver.
The problem occurs when OS X considers the Java process of an application using TestBench (or the node service) to have a native user interface capability, as with AWT or Swing, even when they are not used. This causes the focus to switch from Firefox to the process using TestBench, causing tests requiring focus to fail. To remedy this problem, you need to start the JVM in which the tests are running with the -Djava.awt.headless=true parameter to disable the user interface capability of the Java process.
Note that the same problem is present also when debugging tests with Firefox. We therefore recommend using Chrome for debugging tests, unless Firefox is necessary.