Where did my histogram buttons go?

I recently downloaded 3.2.1 for Mac; my first experience with dt. I’ve been stumbling through it, poking at various UI items as they appear before me and doing massive google searches.

In the process, I think I somehow disabled the histogram overlay with RGB buttons, along with the functionality that lets you to (as the tooltip still falsely tells me I can) “drag to change exposure,” and “doubleclick resets.”

I’m pretty sure I saw those buttons when I first installed dt. So something I did along the way must have turned off the overlay. But what? No idea.

If anyone can help me out, I’d appreciate it.

The overlay should appear when you hover your mouse over the histogram.

I know! But it doesn’t appear. And clicking on the histogram doesn’t do anything.