Seriously there needs to be a second selection tool that lets us scroll through each item in the gallery and select one to throw down and use. Like in minecraft you select a single block from the set. You don’t drop over 100 different types of spawn eggs just to get a sheep.
We're actually working on a new system for selecting individual props and building tiles. It will take a little while before it's ready. But in an upcoming release we'll be adding a feature that allows you to "slot" selected objects into a special "quick bar" and place them whenever you want.