Twitter Lists Modal Scroll?

Does anyone know how to scroll down the popup modal for twitter list members?

This link will open a popup with the list members: https://twitter.com/i/lists/1453308071158091788/members

However, the "Scroll Down" only selects the TL in the background (moves the entire window, not just the modal's scroll bar) -- any suggestions would be great!

Url: http://example.com

Sitemap:
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