1. Pick any bugzilla bug.
2. Click 'Create a new attachment'
3. Notice that the submit button at the bottom of the page is far below the comment field
Created attachment 9124 [details]
Screenshot -- Firefox
Created attachment 9125 [details]
Screenshot -- WebKit
If you click the "Patch" checkbox on this page, some legal text about submitting patches is showing. My guess is that whatever mechanism is being used to hide the text doesn't collapse the space.
Hmm...looks like the culprit is the "visibility: collapse;" style.
Copying Joost on this bug since he's the Bugzilla look-and-feel guru.
This is caused by WebKit treating "visibility: collapse" the same as "visibility: hidden". See http://www.w3.org/TR/CSS21/tables.html#dynamic-effects for information about how it should be treated, and http://www.quirksmode.org/css/visibility.html for an example that compares its behaviour with various settings for the visibility and display property.
*** This bug has been marked as a duplicate of 8735 ***