From time to time I do something, hit some kind of keystroke
combination or I don't know what, that causes the following phenomenon
in e-mail:
The scrollbar runs to the bottom of the message.
The scrollbar in every mailbox runs to the bottom of the mailbox.
It is accompanied by a kind of jittery fluttering of the window contents.
Any attempt to move back up is defeated.  It is not possible to place
the cursor higher up within the text or within the mailbox.  It is not
possible to continue with the message.
Nothing seems to stop it.  Escape doesn't stop it.  Closing the
application and restarting doesn't stop it.  When I come back in, it
is still doing it.  The only solution I have found is to exit and
reboot the system.
I am able to save the message in draft, and when I come back, it is
there and all right.
This happens in both Eudora and Outlook.

I do not know what key(s) I hit to cause this.  I have seen it happen
over at least a ten-year period and through many upgrades of Eudora
and Outlook.

My questions:

1.  What makes this happen?
2.  What can I do to halt it, short of rebooting?

Thank you,
Archae0pteryx

Thinking about the simplest things first, it sounds like you might
have a stuck key on your keyboard (most likely either the down arrow
or the end key).  Alternately, it could be a similar type of
malfunction of your mouse/touchpad.

Assuming you're using a desktop, next time the problem happens, try
unplugging your keyboard and/or mouse, to see if this solves the
problem.

I've had a similar problem from time to time. In my case, it seems to
be a mouse problem, specifically a defective scroll wheel. If I diddle
the wheel a bit, I can usually stabilize the scrollbar.

At least 10 different keyboards, and even more mice, both over a wide
range of vendors and quality, both at home and at work.  Laptop. 
Desktop.  Dell.  IBM Thinkpad.  eMachines.  Macintosh.  Gateway.  It's
got to be triggered by something in the software.  It happens when I
am using the keyboard, not the mouse.  And it always happens when I'm
not looking at my hands.

I'll try wheel-diddling next time, though, Pink, and see if it helps.

Tryx

It's not a wheel problem.

This maddening phenomenon just happened again on my work laptop.  I
was typing an e-mail, and the keys I meant to type were two dashes, or
maybe a space and two dashes.  The auto-scroll kicked in and I could
not stop it.

I closed the mail application.  The same phenomenon was happening in
an open Word file and an open browser.  I opened a PDF in Acrobat and
the same thing is happening there.  If I start something else that I
wasn't even using--yup, PowerPoint:  same story.  It scrolls to the
bottom and keeps going back to the bottom, defeating any attempt to
bring the cursor up.  The last slide in the PPt is flashing now as the
program repeatedly attempts to scroll down further than the file goes.

Same thing when I even access a list of files or e-mail folders.  I
can't get to anything above the bottom of the display because it
scrolls down faster than I can catch anything.

It is as if the jump-to-end-of-file function were being invoked in an endless loop.

It isn't going to stop unless I close everything and reboot.

This is not a mouse problem.  I have an optical mouse--no ball to
twiddle.  It's a keyboard function of some kind.  I was not touching
the mouse when it happened.  Repeat, my hand was nowhere near the
mouse.  I was typing on the keyboard.

There has to be an answer to this.  Something causes this to happen. 
I think it is some special keystroke combination that I hit because my
nails are long.  Surely we have a keyboard hardware or software expert
who knows both the cause and the antidote.

Hasn't anyone else ever experienced this?  Ever in the world?

<very frustrated>
Tryx