Some strange behaviour in Unity Editor

When I work in Editor on Scene, I often saving, navigate over all objects... And in some moment when I press W (hotkey for Move), it start working as F (frame selected). Every press of W focusing camera on object and move camera view. And F stop working. I have to restart Unity, because don't know how it fix. The question #1 is: what it is, why and how to fix it without restart?

Problem #2: when I focused on some object (F hotkey), and start move camera away, in some point on some distance camera moving slow down. Very slow. And vice versa: I select some giant object, terrain for example, zoom in for changing - and sensitivity of moving is very, very huge. Question: how to make camera moving independence of distance to selected object? I know, when it slow, I can press Shift, but in is not what I would want.