Sometimes when you detach a page from page layout using sharepoint designer and when trying to edit this page or editting any web part you may face this error message “This Page has been modified since you opened it. You must open the page again” So in order to fix this issue without de-taching the page to it’s original layout and keep your customization So all you have to do is to open the page in SharePoint designer and add the below script “ MSO_PageHashCode clearing script” :
<script language="”javascript”" type="”text/javascript”">
if(document.getElementById(“MSO_PageHashCode”))
{
document.getElementById(“MSO_PageHashCode”).value=”";
}
</script>
Sometimes , You may face this issue when using any button (like asp:linkbutton or asp:button) for navigating to different URL (i.e: using the postback property) because , it’ll submit page.form , So in order to avoid this you should use normal
or use asp:hyperlink control.
