The example include a series of span displayed as inline element, where the padding-right property has been tweaked to make them displayed into column. It work almost well, except the first line, which is word-wrapped a little too early. Actually, trying to find the minimal bug show case, when I remove the <input type=checkbox> tags, the layout worked as expected.
Created attachment 15757 [details] inline span with padding-right that cause weird layout
Created attachment 15758 [details] inline span with padding-right that cause weird layout
Confirmed difference to Firefox 2.0.0.6 using a local debug build of WebKit r24792 with Safari 3 Public Beta v. 3.0.2 (522.12) on Mac OS X 10.4.10 (8R218). This is not a regression from shipping Safari 2.0.4 (419.3) with original WebKit as it has the same issue. The first row in the test case should have three items in it, but only has two.
Bug description is a bit vague. The test case doesn't look problematic to me on ToT WebKit. Can you close if it looks fixed to you?
Safari, Chrome, and Firefox all agree on rendering for this test case. I don't believe there is any remaining compatibility issue.