IE9 / IE10 CSS shadow not rendered

Yesterday I got the problem that IE does not render the box-shadow property. After a while a figgured out that the property „border-collapse: collapse;“ for a surrounding table prevents the rendering. I got the property inherited from a stylesheet of a JS Framework. After manipulating my css to the following configuration:

.shadowed {
   -moz-box-shadow: 0 0 5px 5px #DDD;
   -webkit-box-shadow: 0 0 5px 5px #DDD;
   box-shadow: 0 0 5px 5px #DDD;
   border-collapse: separate;

it also works for IE, Safari, and Firefox. Thanks to thirtydot who gives me the right clue.