Configuring Your Tile Set
You will more than likely need to configure your Tile Set to ensure that you are accurately selecting each tile within your sheet.
Inside the Viewport, Left-clicking on your Tile Sheet will display a white tile selection box indicating the currently selected tile.
Right Mouse Button drag inside the Viewport to pan and use the Mouse Wheel to zoom in/out on your Tile Sheet.
Above, the default Tile Width and Tile Height (in pixels) of 32 is being used represented by the white selection box. Unfortunately our tiles are larger than the default values and we want our Tile Width and Height to encompass our entire tile (represented by the yellow box outline).
Inside the Tile Editor preview window the currently selected Tile and its associated Tile Number (see below) are displayed. Just below it, inside the Details panel, you can adjust the Tile Width and Tile Height so that it properly encompasses your entire tile.
In our example, we've increased the Tile Width and Tile Height to 64 to match our tile size.
Click for full view.
In the Viewport, the white tile selection box now fully highlights an individual tile on the Tile Sheet (you may need to experiment with different values depending on how your Tile Sheet is set up). The Tile Editor window also updates to show a single tile from our Tile Sheet that is selected.
In addition to setting Tile Width and Tile Height, you can use the following settings to further adjust your Tile Set from the Details panel.
The width of a single tile (in pixels).
The height of a single tile (in pixels).
The amount of padding around the perimeter of the tile sheet (in pixels).
The amount of padding between tiles in the tile sheet (in pixels).
The drawing offset for tiles from this set (in pixels).
The background color displayed in the tile set viewer.