Select dropdown rendering incorrectly on Firefox?

[mqhandelman]

I'm looking at the actual sample page: http://bootstrapformhelpers.com/select

I'm running Firefox 66.0.3 on a Windows 7 desktop.

When I select either Example 1 or Example 2, and then I click the dropdown to view the options, the options appear, but the width of the selection list is so narrow, maybe 10% of the available width, that all that's visible is "Opti..." for each option.

It works fine for me on Chrome and IE 11