I have an absolute positioned div which works like a tooltip. On mouse over of an element it shows and then hides at mouse out. I have few elements i
No element will apply the z-index value without also having a position attribute (absolute, relative, fixed, etc).
z-index
position
Try adding position:relative to your select so that it inherits a z-index value.
position:relative
select
See this screencast for a more in depth explanation.