I often find that I am editing away then gvim randomly does a page scroll. which means I start typing in the wrong place. On the basis that its most likely to be user error, is there some key combination that I am inadvertently pressing?
There are tons of keys that can move you around in
Some of the commonly used navigational keys in
.. so on and so forth.
It might not be a key combination at all.
I find that random scrolling around within entryfields, not just within text editors, happens to me frequently on laptops where the touchpad is enabled, as the heel of my hand accidentally touches the touchpad. I'm far from the only one to have experienced this. This person suffered from this problem too, as did the person answering in all-capitals.
If you discover that this is your problem, the simple solution is of course to turn the touchpad off. The hard part, as can be seen from that question and the number of "How do I disable the touchpad?" questions in SuperUser, is doing that. ☺