Build 39 Can't destroy some walls with sledge

[Flukey]

May be hard to explain, however I found when making floors sometimes I cannot seem to select a wall/fence and instead it show the wall across from it.. For example I have a passageway that is 1 tile wide.. fence on either side. I cannot destroy one of the walls. It keeps selecting the wall/fence across from it. I figured out a workaround, you can disassemble it.  In my diagram below.. the X is the fence i am trying to remove. P is me the player. Y is the panel that highlights when trying to destroy X with sledge.

 

-----I---|---I-y-|

-----I---|---I-x-|

                   P