Tor: Thanks for the quick reply. A checkbox would be ideal, although I would be happy to have it accessible in the config file, since it is more in the line of a user preference (of course, this implies that for multiuser systems, there is a separate config file for each user).
A refinement would be to be able to specify the depth of the sensitive region, i.e., the extent in pixels from the window edge. A depth of 1 would still allow the viewport to be moved by “pushing” the edge of it with the mouse pointer, and a depth of 0 or -1 would in effect disable the auto-scrolling completely.
BTW, is there a list of existing options that are controlled from the config file?