[xenomachina]

There can be weird differences that show up on different operating systems, even with the same browser.

For example, we ran into a difference between Chrome on Linux vs Chrome on macOS where it turns out that on macOS, if you right-click on a link (to open a context menu) it selects the text of the link, while on Linux it does no such thing. Initially we'd tested on only one platform because we assumed they'd behave the same, and this difference resulted in buggy behavior on the untested platform.