Whenever I open the close question dialog on my laptop's 13" display, the upper portion of the popup winds up on top of the "Questions Tags Users..." navigation bar, but due to an issue with the assigned
z-index of the popup versus that of the navigation bar, the navigation bar trumps the dialog and bleeds through.
It appears that by setting the
z-index on the
#close-question-popup to a minimum value of 80, the dialog will then be the prominent element. Alternatively you could take the
z-index of 80 off of the
#hmenus element, although I don't know of the repercussions this may have on the site.
For reference, my I am running Google Chrome 23.0.1271.101 on a 13" MacBook Pro with OSX 10.7.5.