You cannot intermix other parts from one UI into another. Each window relies on another window’s code for it to function. Each UI was created as a whole, not in parts.
In order for that to happen, you would have to hunt down all of the code it is missing that the UIErrors.txt file is saying it needs (errors only, not warnings) and would need to be copied into the target window to accommodate that UI including any graphics it is calling for. Some graphic names uses the same name but different graphic, so that might be a challenge too. Its not an easy task.