I am not quite understanding the model chain parameter. I have a Falcon F48. On port 1 of the first differential controller (so port 1 out of 48) I want to have 4 arches. So in xLights I defined my F48 controller with Auto Layout Models enabled. See attachment F48Controller.png. Then in "Layout" I have 4 arches. Each has "Controller" set to my F48. Port is set to 1 for all of the 4 arches. Then for arch 1 I set Model Chain to Beginning. For arch 2 I set it to >Arch #1 (so following arch #1, that is how I understand it). Arch 3 is set to >Arch #2. But then for arch 4 I don't see the option >Arch #3 but only beginning. Why can I not select arch 3 and is this really the way to do it anyways? My idea is that I have a couple differential controller for the front yard, a couple differential controller for the house outline (one for the 1st level, one for the second level) for a total of just 4 differential controllers. If you need more screenshots let me know what will help to clarify the issue.