Trying to get a css transparent background on an li tag working in IE

Have the follow code which works if I put the 'filter' on the ul or any other element but when I place it on开发者_运维知识库 the li tag it's not working. I've tried adding display:block but no joy. What could be stopping it working? Here's my css code:

.argh li{   
  filter:progid:DXImageTransform.Microsoft.gradient(startColorstr=#4cdddddd, endColorstr=#4cdddddd);
  margin:0 -10px; padding:0.6em 20px; }

PS Css named argh because I've been pulling my hair out with this for a couple of hours now. :)

From the Microsoft gradient filter documentation:

The object that the filter is applied to must have layout before the filter effect will display. You can give the object layout by setting the height or width property, setting the position property to absolute, setting the writingMode property to tb-rl, or setting the contentEditable property to true.