I tested your code, change:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "
http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<%@ Page Language="C#" validateRequest="false" %>
<%@ Register TagPrefix="cutesoft" TagName="banner" Src="banner.ascx" %>
<%@ Register TagPrefix="cutesoft" TagName="leftmenu" Src="leftmenu.ascx" %>
<%@ Register TagPrefix="CE" Namespace="CuteEditor" Assembly="CuteEditor" %>
<html xmlns="
http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<style type="text/css">
html, body, form{ height: 100%;} </style>
</head>
</head>
<body style="margin:0px"> <form id="form1" runat="server" >
<CE:Editor ID="Editor1" runat="server"
ActiveTab="View"
ShowWordCount="False"
Height="88%" Width="88%">
</CE:Editor>
</form>
</body>
</html>
to:
<%@ Page Language="C#" validateRequest="false" %>
<%@ Register TagPrefix="CE" Namespace="CuteEditor" Assembly="CuteEditor" %>
<head runat="server">
<title></title>
</head>
</head>
<form id="form1" runat="server" >
<CE:Editor ID="Editor1" runat="server"
ActiveTab="View"
ShowWordCount="False"
FullPage="True">
</CE:Editor>
</form>
</body>
</html>
html, body, form{ height: 100%;}
and
<body style="margin:0px">, these two styles setting lead to this issue.
Regards,
Eric