While building in the editor, I was unable to select the Marble Block that is 2x2x1 (attached a photo) after placing it down by clicking on it. The only way that I can remove it is by undoing its placement or to drag for a selection.
Meanwhile, I'm able to use all the other Marble Blocks (and every other block I've tried) just fine. I've tried using the block in other files, as well as reloading the game, but it's still unclickable.