Problems with Click Found Image near mouse position

I'm not having any luck getting KM to find an image near the mouse position. I'm using "in area" with MOUSEX() and MOUSEY(), and when I try these with the Highlight Location action everything looks good, but with Click Mouse I only get "No unique image found".

I'll attach a screen shot of a simplified test case, which I'm using in KM itself.

Thanks for any ideas!

Screen Shot 2021-03-15 at 10.21.57 AM