Home » Tip of The Day » Selective FlatteningSelective Flattening November 12, 2016. Posted in: Tip Of The Day. If you want to only flatten some of the layers in a document, click the eye icons to hide the layers you don’t want to flatten, and then choose Merge Visible from the Layers menu. « Previous Photoshop Tip: | Next Photoshop Tip: » Sign-up for the PTC Newsletter so that you'll never miss a tutorial!. Your Email Address: