Deselect a tile without any white space in map layer? +layer issues.

I've taken a liking to building maps using the system's mechanics for doing so, but I'm having a lot of issues. First off, I'd like to deselect a tile somehow- preferably by clicking off the map or hitting ESC. Is there a way to do this currently? Secondly, I've noticed that as I'm adding things, sometimes some of the previously placed items are being pushed to the back, and it's a little frustrating to deal with (though not impossible). Is this a known bug? Thanks for any response! -Crom

I've noticed the second problem myself - I've spent ages building maps on here only to have all the layers rearrange, and suddenly the tables my characters are supposed to be sitting around disappear behind the floor... If there is any way to avoid this happening (short of making the map on a different program and importing it as a single file...) I'd most appreciate hearing about it...