Re: Suggestion: A fringe indicator that shows the last/first line before scrolling

[Stefan Monnier]

> So try this (on X11 at least):

> (add-hook 'post-command-hook
>   (lambda () (message "post-command-hook %s" (current-time))))

> Then activate the region with the mouse, scroll with scroll bar.. no update.

> This might just be a bug, or intentional (though kind of inconsistent)
> behaviour, I don't know.

It's neither.  It's just the result of how the code is written: there's
only one command (the mouse-drag) which happens to read several events
waiting for the event that marks the end of the drag.

Usually each event is associated with a command (modulo commands bound
to event sequences like C-x C-x), but it's not necessarily the case.
There are other cases where scrolling can happen without running
post-command-hook, e.g. scrolling triggered by process filters
(e.g. scrolling in the *compilation* buffer or in tail-mode buffers).


        Stefan