Not sure what the problem is from the image, my guess would be that you've hidden tile indices. You can enable this again by going to view->"show tile indices"
If you want to remap a tile or map a tile from canvas again, use cmd+click on mac and ctrl+click (if I recall correctly) on windows.
You can always verify whether a tile has been mapped by enabling the "show tile indices". A mapped tile will show a number, while a non mapped tile will just be a dot.
For more hints regarding how to use the tile placer tool, hover the cursor over the tool.
Comments
Not sure what the problem is from the image, my guess would be that you've hidden tile indices.
You can enable this again by going to view->"show tile indices"
If you want to remap a tile or map a tile from canvas again, use cmd+click on mac and ctrl+click (if I recall correctly) on windows.
You can always verify whether a tile has been mapped by enabling the "show tile indices". A mapped tile will show a number, while a non mapped tile will just be a dot.
For more hints regarding how to use the tile placer tool, hover the cursor over the tool.