In the layout viewer, right click on it, go to z-index option, send to bottom of layer.
https://drive.google.com/file/d/0BwxSAR ... sp=sharing
If you want it to a top shooter, like your example, when you add some room with walls, create a new sprite to be the floor, then, a new one to be the walls. If the player_los have a lesser z-index, it will stay above the new room sprite. Got it?
You can make this with the following layer order:
3 - rooms walls
2 - rooms floors
1 - player and player_los
0 - background
Sorry about my bad english, im brazilian <img src="{SMILIES_PATH}/icon_e_biggrin.gif" alt=":D" title="Very Happy">