On 2016, every time you select/copy/paste a range, there's a little icon at right-side lower corner of the selection, giving you some options.
If you use they keyboard extensively to navigate throughout Excel, you can unintentionally focus on these options using Ctrl.
I've already disabled the following
Excel Options > Advanced > Cut, copy, and paste > Show Paste Options button when content is pasted
Excel Options > Advanced > Cut, copy, and paste > Show Insert Options buttons
Now, there's one more button that suggests Conditional Formatting, and I want to disable that.