On-screen keyboard viewer not showing up in menu bar in El Capitan

Since upgrading to El Capitan, I've been unable to get the on-screen keyboard viewer option to show up in the menu bar.

I go to System Preferences --> Keyboard and check the box next to "Show Keyboard, Emoji, & Symbol Viewers in menu bar", and then nothing happens.

Nothing additional shows up in the menu bar, and if I click on any other tab in the Keyboard section of System Preferences (or go to another section of System Preferences and return to the Keyboard section), the box next to "Show Keyboard, Emoji, & Symbol Viewers in menu bar" becomes unchecked.

No matter how many times I try checking it, it becomes immediately unchecked when I leave the main tab under Keyboard preferences and then come back to it, and it doesn't add the keyboard viewer option to the menu bar.

I can't for the life of me figure out what is going on.