Dashboard widgets "frozen:" Can't add, delete, or move

What's up?

As the title says, my dashboard appears to be "frozen" in place. I can't reorder subreddit widgets; trying to add widgets does nothing; and any subreddit widgets I try to delete reappear after refreshing the page. These threads (1), (2), (3) look like the same or similar issues.

Everything else seems to be in order.

Where does it happen?

Dashboard

What browser extensions are installed?

Adblock, LastPass, Destiny Item Manager, Destiny tooltips. The problem persisted after disabling all of these.

• Night mode: false
• RES Version: 5.6.4
• Browser: Chrome
• Browser Version: 58
• Cookies Enabled: true
• Reddit beta: false