I was trying to originally make a rainbow colored stained glass wall around a plot in creative, and the glass panes stack on top of each other just fine, but when I moved onto orange from red, the red seemed to connect but the orange stood in it's parameters as if it had been placed alone, in it's little pole shape. I had thought it to maybe be that I was trying to connect two different colors, but I removed the orange and tried to place another red next to my original reds and it still did not work, with the original red blocks again trying to connect and the newly placed red not doing the same. 

I had originally been placing the blocks by placing them on the top of a grass block, but after that failed I tried actually right clicking on the side of my original reds. When I tried this, neither block attempted to connect with the other. They again acted as if they were placed as standalones.

When the glass panes are in rows of standing poles, you can attempt to walk through them but glitch out really badly.

I can provide screenshots if needed and I can try to do a video but I'm not 100% how to record it. I'll figure it out, just ask.