Are you dragging something past the edge of the visible canvas?

-Noel

That's not an auto-scroll function, that sounds like a problem with your system.  I never see that when working in Photoshop, and I certainly wouldn't stand for it.  I've seen it reported from time to time though... 

Do you have a wireless mouse?  Wireless keyboard?

Are  your drivers up to date?

Any chance anyone as a prank installed one of those stupid devices ThinkGeek sells that are designed to irritate you by generating spurious inputs to your computer?

I'm not going to be online tonight much longer, but for others who might want to try to help, please list your system type, operating system and version, and Photoshop version, as well as whether you have all your software up to date.

-Noel

I seem to remember Logitech wireless mouse having that.

Is that an apple magic mouse?

Well therre you have it. It's magic.

This is a terrible problem. It happens, for example, when I have a full-page image open, in full screen mode. Doesn't happen when you have a floating window. BUT I am working with projection mapping, so I must work with an actual-size image, fit to the screen exactly. As a result I simply cannot work near the edge of the image. It's ridiculous that software this mature has such a hole! There must be a workaround! It is definitely Photoshop, not the OS interface, that has this "feature."

Any suggestions welcome....

thank you.

This is a photoshop problem and indeed is `hell` for projection mappers. It is the single pain with using photoshop to `map` on the extended desktop. Any doubters should set up a full screen on their extended desktop and out of a projector and then put a brush mark in the centre of the screen and then whilst holding shift draw a straight line to the edge of the image. The image will immediately jump out of position, done with a selection tool it slides out of position. It is a superior pain and the only solution is to use the `F` key to bring it back to fullscreen. Usually this drops it back to where it was but on some machines it doesn`t even do that right. A switch to turn it off is desperately required!

Sorry Noel - create an extended desktop and open photoshop - create a file the same size as your second monitor and drag it over to the second screen. Press F to make it full screen and Ctl 1 to make it actual pixels. We now have just what we require for projection mapping onto say a building assuming the second monitor is a projector. Now take a brush and stamp it in the middle of your page - which is on the second monitor, photoshop itself is on your Ist monitor. If you press hold Shift down and stamp your brush at the edge of your full page you will see it jump too the side. It will also do this if you try to drag a selection too close to the edge. The page will begin to scroll to accomodate the selection which is perhaps useful in some circumstances but in others like to projection map it is a horror because we need the page to remain exactly where it is at all times or it will no longer be `registered` to the architecture previously done. Beleive me

this can be deeply frustrating when you are out in the cold trying to get all the facets of a building mapped, but even when in the warm trying to do it with a theatre set. 

Should you have a solution then you would indeed become much revered in these parts  - best wishes  John   --

 a couple of mapped buildings done with this method below

http://vimeo.com/31496197               ness chrurch

http://vimeo.com/17762125                 xmas lights

As John says, at least with the two-monitor setup one uses with the projector going, the full-screen (projector) monitor will move with the selection tool near the edge. There is no way to defeat this behavior. My workaround was to abandon the selection lasso and instead use the pen tool. This works fine, there's just an extra step to make the selection. For whatever reason, the pen tool doesn't cause the problem, while selection lasso does. FYI, I was working on lighting the Crossing Borders exhibition at the Jewish Museum in NYC. Check it out if you're in the area. /Eric

Cheers Eric - hadn`t tried the pen, as i said I usually use the Brush tool and the straight line command from holding shift down. On a big building it can be hard seeing the tools that use just a crosshair, the brush can usually be located much easier!  John  - do you have a link to the exhibition?

Yep - agree it needs those three choices ..............