[tlug] Jiggling PDFs

["Stephen J. Turnbull" <turnbull.stephen.fw@example.com>]

Brian Chandler writes:

 > I am looking at PDFs with the Evince viewer -- it's OK, in the
 > ordinary sort of way, but (perhaps with a recent "downgrade") it
 > has started hyperactice scrolling. If the mouse is outside the
 > window it keeps scrolling up or down, for no reason, other than to
 > irritate me.

Is the window moving when the mouse is stationary? Is the window
focused (usually the frame is a special color and is the only one
accepting keyboard input, except for window manager shortcuts)?

What window manager (if you don't know that, what desktop; if you
don't know that, what distribution) are you using?  If your system has
a touchpad, is it active?  (Many systems offer a mode where both a
mouse and the touchpad are active.)  Is any part of your body near it
(< 1 cm)?[1]

 > Does anyone know how to disable this (and every other stupid
 > "feature" if possible)?

I would downgrade Evince to the previous version, since you think this
is related to an upgrade and did not occur previously.  Unless you
upgraded deliberately because of improvements claimed for the new
version.  In that case you should report a bug to the developers and
to the distro (making it clear that you have reported to both).
Reporting the bug is good citizenship even if you decide to use a
different version, or a different application.  The answers to the
questions above will likely be needed by the developers.

The problem is not "features", it's "stupid".  Somebody thought that
whatever feature they were trying to implement was not stupid.  What
you have observed is almost surely a bug.  Probably there is an
unexpected interaction between the application and the window manager,
probably there's a bug in implementation of one or the other, or a
poorly documented case in the window management API, or possibly a bug
in the underlying window system.

You have a choice.  You can live without features, or you can live
with stupid ones, or you can build your own system.  But even in the
last case, you'll have to live with bugs (although you can fix the
ones you care a lot about more quickly.


Footnotes: 
[1]  Touchpads detect electrical potential of your skin, not touch.
The actual distance where it activates of course is much closer (< 1
mm), but it's not easy for most of us to remember hand position to
less than 1 cm.