I have this issue as well with folders with lots of files and or subdirectories. I'm not sure where a long time ends and a hang begins, but I just went and made a cup of coffee and the window which contains WinSCP is still just a blank white pane. I'm using version 4.04. It's faster to kill winSCP and login again than finish the coffee and get another cup while waiting for a refresh to finish. In fact on the directory I'm thinking of, I'm not sure if I've ever managed to wait it out to be honest.

It probably does not hang, it just takes a long time to load the folder. Especially if there is a large number of symlinks. You may try to disable symlink resolution then.

We have a folder with several thousand files in it.
If you browse to this folder with WinScp it hangs. Vry annoying