If I use Inplace edit the grid is displayed correctly.
<telerik:RadGrid ID="gvCountry" runat="server" CssClass="RadGrid" GridLines="None" ShowFooter="True" ShowStatusBar="True" CellSpacing="0" VirtualItemCount="100000"
PageSize="20" AllowPaging="True" AllowCustomPaging="true" AlternatingItemStyle-BackColor="#FEE4EFFF" AutoGenerateColumns="False" AllowSorting="True"
AllowFilteringByColumn="True" OnInsertCommand="gvCountry_ItemInserted" OnUpdateCommand="gvCountry_ItemUpdated" OnDeleteCommand="gvCountry_ItemDeleted"
OnItemDataBound="gvCountry_ItemDataBound" OnItemCreated= "gvCountry_ItemCreated" OnItemCommand="gvCountry_ItemCommand" OnNeedDataSource="gvCountry_NeedDataSource"
OnDetailTableDataBind="gvCountry_DetailTableDataBind" OnGridExporting="gvCountry_GridExporting" OnExcelMLExportStylesCreated="gvCountry_ExcelMLExportStylesCreated" GroupingSettings-CaseSensitive="False">
<MasterTableView CommandItemDisplay="Top" DataKeyNames="CountryId" Name="Country" EditMode="EditForms" >
<CommandItemSettings ShowExportToExcelButton="True" ShowExportToPdfButton="True"/>
<DetailTables>
<telerik:GridTableView DataKeyNames="CityId" Name="City" CommandItemDisplay="Top" Width="100%" EditMode="EditForms" PageSize="10" VirtualItemCount="1000"
AllowPaging="True" AllowCustomPaging="true">
<EditFormSettings EditFormType="Template">
<FormTemplate>
<table id="CityEditTable" style="border-collapse: collapse; border-spacing: 0.2em; position:static;
*border-collapse: expression('separate', cellSpacing = '0.1em'); width: 100%; border: 0;">
<tbody>
<tr class="EditFormHeader">
<td colspan="4" style="font-size: small">
<b>City</b>
</td>
</tr>
<tr>
<td> <asp:Label ID="dlglblDistrict" runat="server" Text="District"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtDistrict" runat="server" Text='<%# Bind("District") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblCityName" runat="server" Text="CityName"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtCityName" runat="server" Text='<%# Bind("CityName") %>'></asp:TextBox> </td>
</tr>
<tr>
<td style="text-align: center" colspan="4">
<asp:LinkButton ID="btnUpdateDetail" runat="server" CausesValidation="true" Text="Insert" />
<asp:LinkButton ID="btnCancelDetail" CommandName="Cancel" CausesValidation="false" Text="Cancel" runat="server" />
</td>
</tr>
</tbody>
</table>
</FormTemplate>
</EditFormSettings>
<Columns>
<telerik:GridButtonColumn ButtonType="ImageButton" UniqueName="reg_editDetail" ItemStyle-HorizontalAlign="Right" CommandName="Edit" ImageUrl="~/Content/Images/Edit.gif">
<HeaderStyle Width="2%" />
<ItemStyle HorizontalAlign="Right"></ItemStyle>
</telerik:GridButtonColumn>
<telerik:GridBoundColumn SortExpression="District" HeaderText="District" HeaderButtonType="TextButton" DataField="District" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn SortExpression="CityName" HeaderText="CityName" HeaderButtonType="TextButton" DataField="CityName" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridButtonColumn Text="Delete" CommandName="Delete" ButtonType="ImageButton" ConfirmDialogType="RadWindow"
ConfirmText="Are you sure you want to delete this registration?" ImageUrl="~/Content/Images/Delete.gif">
<HeaderStyle Width="2%" />
</telerik:GridButtonColumn>
</Columns>
</telerik:GridTableView>
</DetailTables>
<EditFormSettings EditFormType="Template" >
<FormTemplate>
<table id="MasterEditTable" style="position:static; border-collapse: collapse; border-spacing: 0.2em; *border-collapse: expression('separate', cellSpacing = '0.1em'); width: 98%;">
<tbody>
<tr class="EditFormHeader">
<td colspan="6" style="font-size: small">
<b>Country Details</b>
</td>
</tr>
<tr>
<td> <asp:Label ID="dlglblName" runat="server" Text="Name"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtName" runat="server" Text='<%# Bind("Name") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblArabicName" runat="server" Text="وطن"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtArabicName" runat="server" Text='<%# Bind("ArabicName") %>'></asp:TextBox> </td>
<td></td><td></td>
</tr>
<tr>
<td> <asp:Label ID="dlglblNationality" runat="server" Text="Nationality"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtNationality" runat="server" Text='<%# Bind("Nationality") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblArabicNationality" runat="server" Text="جنسية"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtArabicNationality" runat="server" Text='<%# Bind("ArabicNationality") %>'></asp:TextBox> </td>
<td></td><td></td>
</tr>
<tr>
<td> <asp:Label ID="dlglblCurrencyCode" runat="server" Text="CurrencyCode" ></asp:Label> </td>
<td> <asp:TextBox ID="dltxtCurrencyCode" runat="server" Text='<%# Bind("CurrencyCode") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblCurrencyName" runat="server" Text="Currency" ></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtCurrencyName" runat="server" Text='<%# Bind("CurrencyName") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblArabicCurrencyName" runat="server" Text="عملة"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtArabicCurrencyName" runat="server" Text='<%# Bind("ArabicCurrencyName") %>'></asp:TextBox> </td>
</tr>
<tr>
<td> <asp:Label ID="dlglblContinent" runat="server" Text="Continent" ></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtContinent" runat="server" Text='<%# Bind("Continent") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblRegion" runat="server" Text="Region" ></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtRegion" runat="server" Text='<%# Bind("Region") %>'></asp:TextBox> </td>
<td> <asp:Label ID="dlglblGovernmentForm" runat="server" Text="GovernmentForm"></asp:Label> </td>
<td> <asp:TextBox ID="dlgtxtGovernmentForm" runat="server" Text='<%# Bind("GovernmentForm") %>'></asp:TextBox> </td>
</tr>
<tr>
<td style="text-align: center" colspan="6">
<asp:LinkButton ID="btnUpdate" runat="server" CausesValidation="true" Text="Insert" />
<asp:LinkButton ID="btnCancel" CommandName="Cancel" CausesValidation="false" Text="Cancel" runat="server" />
</td>
</tr>
</tbody>
</table>
</FormTemplate>
</EditFormSettings>
<Columns>
<telerik:GridButtonColumn ButtonType="ImageButton" UniqueName="reg_edit" ItemStyle-HorizontalAlign="Right" CommandName="Edit" ImageUrl="~/Content/Images/Edit.gif">
<HeaderStyle Width="2%" />
<ItemStyle HorizontalAlign="Right"></ItemStyle>
</telerik:GridButtonColumn>
<telerik:GridBoundColumn UniqueName="CountryId" HeaderText="ID" DataField="CountryId" ShowFilterIcon="false">
<HeaderStyle ForeColor="Silver" Width="20px"></HeaderStyle>
<ItemStyle ForeColor="Gray"></ItemStyle>
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="Name" HeaderText="Name" DataField="Name" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="ArabicName" HeaderText="وطن" DataField="ArabicName" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="Nationality" HeaderText="Nationality" DataField="Nationality" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="ArabicNationality" HeaderText="جنسية" DataField="ArabicNationality" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="CurrencyCode" HeaderText="Code" DataField="CurrencyCode" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="Currency" HeaderText="Currency" DataField="CurrencyName" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="ArabicCurrencyName" HeaderText="عملة" DataField="ArabicCurrencyName" AutoPostBackOnFilter="true"
CurrentFilterFunction="Contains" ShowFilterIcon="false">
</telerik:GridBoundColumn>
<telerik:GridButtonColumn Text="Delete" CommandName="Delete" ButtonType="ImageButton" ConfirmDialogType="RadWindow" ImageUrl="~/Content/Images/Delete.gif"
ConfirmText="Are you sure you want to delete this registration?">
<HeaderStyle Width="2%" />
</telerik:GridButtonColumn>
<telerik:GridBoundColumn UniqueName="Continent" HeaderText="Continent" DataField="Continent" AllowFiltering="false" Visible="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="Region" HeaderText="Region" DataField="Region" AllowFiltering="false" Visible="false">
</telerik:GridBoundColumn>
<telerik:GridBoundColumn UniqueName="GovernmentForm" HeaderText="GovernmentForm" DataField="GovernmentForm" AllowFiltering="false" Visible="false">
</telerik:GridBoundColumn>
</Columns>
<NoRecordsTemplate> <div>There are no records to display</div> </NoRecordsTemplate>
</MasterTableView>
<ExportSettings HideStructureColumns="true" ExportOnlyData="true" IgnorePaging="true" OpenInNewWindow="true">
<Excel FileExtension="xlsx" Format="ExcelML" />
<Csv ColumnDelimiter="VerticalBar" />
</ExportSettings>
<ClientSettings>
<ClientEvents OnRowDblClick="RowDblClick"></ClientEvents>
</ClientSettings>
</telerik:RadGrid>