I’ve just started using Unity and while using the terrain tools the Scene view within the editor will no longer respond to camera controls – middle click to pan, right click to mouse look.
I can still interact with the scene, select objects, use F to focus, use the Perspective/Ortho gizmo, etc. I am also able to right click/middle click things in project view and elsewhere in Unity. There are no error messages in the console, the only other object besides the terrain is a Directional Light set to sun.
Points when it has happened: raise/lowering terrain, paint texture terrain, and just now with smooth terrain.
If I save my scene and relaunch Unity everything goes back to working.
So I just found this error as well and I just found a quick fix I think. Not much of a fix, but if you move the camera how you would normally, but behind you it seems to work. So if that seems confusing just hold shift + right click and then A or D but in the backwards direction. I seem to be able to move normally (obviously except for the fact that I have to do it backwards =/).