Yes, it is. Download, launch, enter your password, let it do its thing, then restart and check if this fixed the issue.

NaOH, tried that. Still the same.

In post 17 NaOH suggested a new user account. You mention a "test account" in 18--but is it a new account (one that has no modifications)?

your pdf has not been processed by OCR and you are just selecting the images of the columns

you will need to run your pdf through an OCR program (such as acrobat pro) first, then
it should be possible to select the text

good luck

This has already been ruled out. The PDF does have text.

I'm not sure what the difference is. Can you explain a bit more?

If your test account was created just for evaluating this PDF issue, then there isn't anything else to do for this evaluation step. If you logged in to a secondary account you've had for a while in order to test this PDF issue, then it's probably best you redo the test in a brand-new user account. We're just trying to assess if the issue is with your system or with your user account. One way to determine this is with a clean, unmodified user account.

I created a fresh new account. Pdf behaviour still wonky. Is there anything else to be done?

Okay, re-reading this thread to see if any ideas come to mind, the quoted post gives me an idea (bonus credit to benwiggy for one of his recent threads). Quit Preview, then delete (or move to the Desktop) all of these:

~/Library/Preferences/com.apple.preview.XXX (I have five files with names beginning this way)

~/Library/Containers/com.apple.Preview

If this works, I suspect the preferences files won't matter but the Container folder will, but it's probably easiest to just remove them all.

I appreciate you digging into this, NaOH, but ... no joy. I did exactly as suggested. Same prob.

Does this mean I'm stuck with it like this, do you think?

10.7.3 came out today. Try installing that and see if that improves matters.

You're sure you haven't got anything installed that might affect system highlighting, cursors or other "cosmetic" features? Or some Input Manager that affects text in some way? Some little cute utility that runs in the background doing something useful?

A new account rules out a problem with prefs, and you've reinstalled the Combo updater, so that suggests there's still something on your OS that's causing the problem.

I've whacked 10.7.3 on, and no change in pdf behaviour. I can't think of anything obvious from the types of thing you mention that could be causing the problem. Is no one else at all seeing anything like this non-highlighting of mine?

Silence suggests you're alone.

How did you get a mauve highlight (post 20)? By changing System Preferences? Or was it perhaps a theme changer of some sort?

If you used System Preferences, use it again to return to the default blue highlight. Any effect on Preview?

If you used a theme changer, tell us more.

In that new user account that you set up, what color shows up as a highlight in Preview, mauve or default blue? In that new user account, what color is showing up as a highlight in another Apple app such as TextEdit?

The (to be accurate) purple highlighting was indeed a System Prefs pref change.

I don't even know what a theme changer is.

I put it back to blue; no effect on Preview.

In the new user account, highlighting is default blue in Preview and in TextEdit.

Returning to NaOH's suggestions in post 29, was Preview closed when you were trashing (or moving) preferences? An open application often "hangs on" to its old, deleted preferences because of the way the OS writes plist files.

A "theme changer" is an app such as CandyBar, http://panic.com/candybar/. It provides a different look to the user interface by making reasonably innocuous under-the-hood changes in parts of the OS many users choose not to stray. The "input managers" benwiggy mentions in post 32 make more radical--and potentially crippling--modifications in order to change the interface, user interaction, and/or core functions (such as highlighting text). But if you remember installing nothing of the sort, then it doesn't matter.

Might you reinstall Preview only? It would be simple enough under Snow Leopard, using Pacifist, http://www.charlessoft.com/, to reload the app from the OS install discs, but I haven't upgraded to Lion and can't say how Pacifist works in the Lion's new disc-less ecosystem.

Preview was closed when prefs trashed. Anyway, tried reinstalling - no change.

Oh, and just a thought: is there NO ONE out there also experiencing this problem. Really? No one?