I noticed that if I right click on tha ad itself to use the preview tool, it shows off topic ads. But if i right click on the text in the page, the preview tool shows correct ads.

However I prefer to find the URL of an ad by right-clicking the ad and then selecting Copy Shortcut, then paste into Notepad.

Anyway, I just tried the preview tool and it worked fine for me.

I noticed that if I right click on tha ad itself to use the preview tool, it shows off topic ads.

No wonder, as this would be the ad preview for pagead2.googlesyndication.com/pagead/ads?client=..., and not for your page.
And pagead2.googlesyndication.com/robots.txt forbids spidering.

So the funny thing is: AdSense has no clue what it's ad pages are about... ;-)

Not exactly. That would be the ad preview for that little space on the page within the iframe that is created by the adsense javascipt on your page when it's rendered. There's no "there" there, so Adsense cannot show relative ads for it.

I consider the tool fundamentally broken:

IE only (they should know many webmasters don't even use a windows box to start with)

not all ads are listed

way too much work to click through all geo-targets

I'd rather have a decent report in my adsense interface and have the ability to ban advertisers, ads and topic there.
All in one page.

I consider the tool fundamentally broken

I entirely agree with you. Google makes it very difficult for publishers to see what's going on on their site.

And don't you find it amazing that Google never bothered creating a preview tool for Firefox?