Several questions about Atlas

After going to Atlas, I did five experiments according to the lab. It was still quite smooth, but I encountered two problems, so I recorded them.
1) In experiment 3, when you enter company and the like, after a smart sensing prompt appears, press the search button
Inexplicably, "" 'null' is null or not an object "appears in seconds. This is really strange. Later, let's look at the answers from foreigners.
Change <Div id = "completionlist"/> to <Div id = "completionlist"> </div> to run the command, but why? It seems that no answer is found yet.

2) The most strange thing is the last lab 5. I used the project created with the blank template of Atlas to follow the steps. On the final page, all the Atlas labels were highlighted in red, unable to switch to the Desgin status (although it can run properly); I will use the dedicated template of Atlas Lab (it is estimated that it is a template provided by Microsoft to facilitate the experiment) to create a new one. It was successful. At the beginning, there was no red warning for those Atlas labels, But it ran two or three times. When I tried to switch to the Desgin status again, it didn't work. It was really depressing. It is probably a small bug in Atlas, although it does not affect the operation.