Try setting the z-index of the dialog.
Ex:
$("#myModalDialog").dialog({
resizable: false,
height: 'auto',
autoOpen: false,
title: "Warning",
width: 200,
modal: true,
zindex: 3999,
buttons: {
'Close': function () {
}
}
});
Refer:
http://docs.jquery.com/UI/API/1.8/Dialog#option-zIndex[
^]