To further Curt's note:  Check Edit - Preferences - Performance.

Assuming you find that OpenGL is not and cannot be enabled, and the dialog says something like "No GPU Options Available in Photoshop Standard", and you have a reasonably modern video card in your system, you may be able to gain access to the Enable OpenGL Drawing setting by downloading and installing new video drivers from the web site of the manufacturer of your video card.

If Photoshop refuses to allow the OpenGL setting after drivers are updated, you may need a new video card to take advantage of the most modern features, such as scrubby zoom, flick panning, and brush size/hardness preview gestures.

What kind of video card do you have?

-Noel

I have the same problem. The scrubby zoom worked yesterday, today it's disabled and the regular zoom does the job instead.

I do have the Open GL checked.

I can't check it, greyed out. All other GL functions dose'nt work either, like the new colorpicker.

EDIT: i installed 3Ds max yesterday, could this have something to do with it?

Your system has a problem, Giallo_1986.  Photoshop did not find that your video card / driver provides sufficient error-free functionality to allow it to enable OpenGL operation.

The advice already given in this thread is right on:  Try newer/different display drivers, remove other apps that might interfere with OpenGL operation, or possibly upgrade your video card to a modern model.

-Noel

Actually, it sounds more like malfunctioning display drivers.  It may be that the latest driver that you have installed has a bug in it.  Such bugs are more common than you might think.

Display driver writers are pressured to release their software quickly, with a huge focus on video games, not on professional, error-free operation such as is required by Photoshop.  Given the fact that updated display drivers fix many problems, that implies that there are versions released that HAVE many problems.  All the companies release drivers with bugs...  In my experience Intel is the worst, nVidia is pretty good, and ATI is slightly better than nVidia, with regard to display driver quality.

Sometimes in isolated cases people even find that removing the latest and installing older drivers can correct problems.

What video card do you have, and what display driver version do you have installed?

-Noel

P.S., I have used Photoshop for hours upon hours without loss of OpenGL functionality.  It IS possible.

Thanks for the tips, I bet they're useful for everyone's reading.

I know about bugs and drivers, they come together often eheh.. in the past I've even experienced problems with OpenGL in PS, recently just having problems with the scrubby zoom and the animated eye dropper.

Weird cause everything else was running nice and smooth, and looking at the Preferences the OpenGL was activated and working fine. Now I've also reinstalled PS and everything works fine again.

And as you said we can't escape to the fact that loss of OpenGL functionality is possible in any case, I often Purge the Histories and the Clipboard to keep things running cleaner.