Thanks for the details.
well in Lix; I have my hokey set to the right mouse button (which can have more the one effect/a hotkey can do multiple things/I have it also select walker. (no this has never interfered with gameplay) something that if this is not currently possible in NL, should be.)
To allow that, I have to change completely how the hotkeys are stored internally. While certainly not impossible, this will be quite a lot of work and therefore not something that will happen in the near future. Sorry.
When I hold the button down then wherever I move my mouse the screen scrolls and (this is important I think): the mouse remains still.
The problem here is, that this is extremely difficult to code. I might manage that in C#, but I don't have any chance at this in Delphi. The main problem is, that the mouse movement is done by the OS (Windows) and it just tells NeoLemmix (or any other application) where it is and when if was clicked. So to keep it standing still, I would have to override the standard behavior of the OS, which is rather hard.
Also it's sluggish; the scrolling starts slowly then goes faster then slows as it stops and sometimes keeps going a little after you stop, as Simon said. You don't have as much control over it.
That's something that can be changed more easily. I guess a constant scrolling speed (perhaps depending on the level size) is preferrable to you then?