Change your Global Default
Tests in PreFlight can have global defaults. You can set global defaults by going to Test Settings > Browsers page. Click the checkbox next to each browser you wish to use for all tests by default.
Overriding Global Defaults
Now you’ve set your global defaults, you may find tests you want to run on more or fewer browsers. You can override the global defaults by going to the test you want to edit then clicking the Browsers dropdown in the test settings options (towards the top).
You can also change tests settings in bulk, by using the selecting them on the All Tests or from a test group page.
Testing on Specific Browsers - One time only
You, of course, also have the option to test on any browser combination you wish, on-demand. Go to the All Tests page then select the tests you wish to test. Click the Run All Tests dropdown and choose
Run All with Custom Settings option. In the browsers section select the browsers you wish to test on. Then click the
Run All Tests Now button which is located at the bottom of the page.
And there you have it! Your tests will run with the browsers you want without overwriting your global defaults or test-specific settings.