The issue I'm facing is with the AJAX Control ToolKit Modal Popup's background (the blind curtain) disappearing after scrolling up and down several times. I have attempted to resolve this by applying various CSS styles, but unfortunately, none of them seem to work as expected.
.modalBackgroundIssue
{
filter:alpha(opacity=70);
padding-left: 0px;
background-color:Gray;
color: #000000;
vertical-align: top;
padding-bottom: 0px;
padding-top: 0px;
}
.modalBackgroundFix
{
position: absolute;
z-index: 100;
top: 0px;
left: 0px;
background-color: #000;
filter: alpha(opacity=60);
-moz-opacity: 0.6;
opacity: 0.6;
}