There's this thing called 'Transparent selection'. Once you select an area with that, all empty tiles will be ignored. They are still technically part of the selection, but they are not dropped when you unselect. In Options it's under 'Draw mode', or there's a button in the toolbar for it. It has a convenient icon that looks like selected tiles over stuff Take a look at the screenshot I put with DCME in the downloads section. The selection you see is actually a rectangular one, with the Transparent selection mode See also: Draw under; Draw or move tiles without affecting any of the tiles already placed, or if you prefer, draw or move them UNDER the tiles in place. That affects both selecting and drawing with tools such as the line. Transparent selection has no effect on drawing, obviously.