I installed Thumberweed in my new Dell XPS 15 laptop. When I closed the lid of my laptop, it is suspended. However, when I open the lid, all the opened windows are gone… It looks like I just log off instead suspended.
I’m not able to see your laptop screen. So I’m guessing.
When I suspend my system that way, after opening the laptop I still have to press the power button to get to the screen.
I never actually do that, except by mistake, so again note that there some guessing here.
I next see what looks like a login screen. But it is really from the screen locker. I have to enter my password to unlock the screen to see my windows.
If that does not work at all for you, you could try CTRL-ALT-F1 to see if you get a command line login prompt. And at that point, maybe CTRL-ALT-DEL to reboot the computer might be the next step. Suspend and resume does have problems with some graphics display cards. It seems to work okay with Intel graphics, and that’s all I can test with my current computers.