Users can reorder the tiles by dragging the whole item space. Use the reorderable boolean property to configure dragging.
Dragging a tile in the direction of an adjacent tile will push the adjacent tile down on the next row but on the same column-line. The initial placement of the dragged tile can be filled by another, if it fits and if it's on the same column-line. Non-reorderable tiles can fill gaps from reordering other tiles.
Note: The reordering functionality is enabled by default.