"Original time" popups sometimes below other page elements

[olane]

On this page, for example: http://www.theverge.com/2012/8/2/3215238/the-vergecast-is-live-today-1-30-pdt-4-30-edt-8-30-gmt-9-30-bst?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+ThisIsMyNextPodcast+%28The+Vergecast%29

Tried setting the hoverStyle's z index higher than the image it appears behind, but it didn't make a difference. There isn't an upper limit to CSS z-indexes, is there?

[lavelle]

Maybe the best way to fix this is to have the popup appear at a fixed point in the page, say the top left.
It can be kind of messy having it appear below the converted time because they can be anywhere on the page so it could obscure other information or be off the edge of the page.
It would also be easier to compare two times if they appear in the same place. It wouldn't solve the problem, because a logo image could still be positioned to be in front of the popup, but it would make it less likely to occur.
Still haven't been able to determine why it's behind the images on that page.