Hi [NAME] Xu  thank you for the videos, they were really good at demonstrating the problem. It seems that the LCD screen's connector is not fully captivated. This will not fix itself. Please Reject and request new replacement as soon as possible. Dell Refund policy, New vs Refurbished - Dell Community 
I just had this computer. The first time I turned it on, it had this problem. Every time I touch my laptop, there is a chance that my computer LCD will flicker white. I don't know how to describe it in detail. And every time I accidentally touch the LCD, there will be a partial white screen. And I used the supportassist to check all of the items on my laptop, which passed all of them. So I am really confused about why my laptop has this problem? [URL]  [URL] 
m15 R5, LCD problem