I used back in the days a lot of the stable building pieces cause I could get nice windows out from the Wooden Support Strut and Stable fence as wella as from Lettice Wall and stable fence. But now if I try to do this they replace the wall I placed before. Why the change? It was so good to use these combinations to build windows 
I believe @Eradicati0n showed a trick for this in a recent video - if I recall correctly, it was necessary to start with a ‘passthrough’ piece (there were a few examples from different sets - one from the Aesir expansion, another from the Yamatai expansion (not original Yamatai set), but I’m pretty sure there was also one from the stables set - ‘pillars either side of an open space’ - I can’t remember it’s proper name). The idea was, you place that, then place the fence, then replace the ‘passthrough’ piece with the desired wall. I hope that helps, or maybe someone else can be more precise with the details.
Thanks! That helped a lot 