Selects (v5+) triggers wrapping form submit

[pimschaaf]

Issue description
Clicking the listbox appears to trigger submit instantly when the listbox is nested in a <form> tag.

Example
Used https://github.com/dequelabs/pattern-library/wiki/selects example code, nested in <form> tag.

See https://codepen.io/openroads/pen/rNOKEwP (sorry, Font Awesome is missing here)

Expected behavior
I'm new to this library, but I'd imagine the select would keep a value until submit is triggered either by something like <input type="submit"> or JS submit().