You are correct, there is no need for a drop down box if it is only going to give you one option. When I passed through this section of code I was in a "get things working" frame of mind and less in a "how things should probably end up working" mind set. I was hoping to get back to code like this and clean it up but instead ended up running out of time.

The color format, from what I understand, is now set in this line:
videorate_cap.set_property("caps",
                        Gst.caps_from_string("%s, framerate=%d/1, format=Y444" % (self.input_type, self.framerate)))

in the __init__.py file. I have it hard set to Y444 for now, but that drop box should be repurposed to change that.
.