Because this question seems to be frequently asked (by me at least), and because I want to help make the answer easy to locate:
Internet Explorer obviously has issues, but despite the fact it should be relegated to the trash heap of buggy software that doesn't perform nearly as well as its competition IE will be with us for years to come. One of the many issues I've had programming cross-browser sites has to do with empty overlay elements.
For example I set up a quick 'n dirty landing page consisting of one page sized image that needs to have a clickable link embedded in it. There are two options: create an image map, or simply use absolute positioning to overlay an empty HTML element (such as an A or DIV tag) at the appropriate location.
I prefer the latter process, but IE won't layout an empty element that has its CSS background property set to 'transparent' - this is true even when the element is given a height and width! The only workable solution I've found is to give the background a color and then make that overlay element transparent via the CSS opacity functionality. So here's a good cross browser example of the CSS code required:
element{
background:orange;
opacity:0;
-ms-filter:'progid:DXImageTransform.Microsoft.Alpha(Opacity=0)';
filter: alpha(opacity=0);
}
Setting the background color forces the IE layout, but then we need to assure the element isn't actually visible to the viewer. Easy to do.