I don't think it IS a bug in IE. Since it is a behaviour, not to fill "scripted" variables... It does it on anything that user changed without changing page.
Beside, I don't think IE will change its behaviour to re-fill javascriptted variables on history go...
Therefor, be it a bug in IE (that is there over tens of years) or be it behaviour, I'm looking for a solution...
May be re-check onload...
EDIT:
Nevermind, problem solved by changing Hide function on inc_datepicker.js to:
function Hide(o){
if (!o.disabled) {
// o.disabled = true;
o.selectedIndex = 0;
// o.style.visibility = "hidden";
}
}