2 photo grid view

After installing the new version of Lightroom, I can't seem to figure out how to view 2 different photos side by side. (not the same photo of before and after). I need to compare the 2 different photos and match the background color. I've tried to search online and can't seem to find anything. They used to have the x/y box option in the grid view. That completely disappeared. Can someone please help me. Thank you.