Can't enable 'Reduce padding spaces for list items'

[dylanmorroll]

When I select the 'Reduce padding spaces for list items', it never seems to save. The other checkboxes around it do.

Here's my preferences page:

I select this checkbox and the one below it and hit save:

When I refresh the page, the reduce padding spaces checkbox is no longer enabled, and isn't functioning:

I tried enabling the debug logging but nothing seems to appear in the console for the preferences page.