Fences, glass panes, walls and iron bars currently do not get block state (east/north/south/west) set to true when placed alongside vertical slabs.

Having those blocks extend to vertical slabs would allow for some interesting decoration options (like thin walls with glass windows, etc.).

Currently posts work as you would expect (i.e. they form a connection with the north slab), but they don't form connection with sideways slabs (as those in east and west). I'm not sure about fences and walls in this case, but having glass panes connect with slabs to east and west would be useful for building windows and the like.

Hi! Thanks for the issue. This will be fixed in the 1.12 version as soon as it is released. I'm working on fixing this in the newer versions but am really unsure how to change this behaviour as whether the pane connects now depends on the collision box for the vertical slab and whether it is a full face. This means that only the north face in the example you showed will connect and gives the behaviour we are seeing. There seems no apparent way to hook into this without changing the collision box which means that the collision for the vertical slab will be incorrect. I'm in a bit of a dilemma but I'll see what I can do :)