Imagine, as you double clicked a file on the left, it suddenly scrolled down 3 lines. It could cause you to click the wrong file. Today it happened and it took my site down. A file went someplace it shouldn't have, and due to behaviors in PHP that took me some time to understand, it broke everything. (What actually happened was this file moved up a directory, but it was still in the include path. So it was being included, but from the wrong location. This is my fault for using relative include paths in the first place. Don't do that, this is why.)
The way it sometimes scrolls around right as you click is similar to what Win7 file explorer does. I don't know how WinSCP works internally, but if it's using some Windows widget, that's where the behavior might come from. I don't write many visual applications in Windows but I can imagine such a thing happening.
Anyway, be careful when you click, in Windows 7 at least.