I'm not finding any one cause to this issue, it sea,s to have something to do with the line height and width settings on the body tag:
background-position: left 160px;
font-family: "Trebuchet MS", Helvetica, sans-serif;
margin: 0 0 0 0; /* Sets the margin properties for an element using shorthand notation (top, right, bottom, left) */
padding: 0 0 0 0; /* Sets the padding properties for an element using shorthand notation (top, right, bottom, left) */
text-align: center; /* Centers the page content container in IE 5 browsers. */
try commenting those out.
The google map V3 API does not offer a way of customizing the info window and adding rounded corners.
for the marker icons:
This is a bug we have identified in Design Extender, we will be releasing an update early next week, this issue should be included in that update.
do a search for :
and replace each instance with:
to update the marker image paths top the correct location.