hi Viktor

here i am providing the sample code,  you can check the webtab using contentpage and normal page then you can able to see the difference, 

<ig:WebTab ID="WebTab1" runat="server" EnableValidation="False" Height="500px" StyleSetName="Default"
            Width="486px">
            <Tabs>
                <ig:ContentTabItem runat="server" Text="Tab 1" EnableDynamicUpdatePanel="True">
                    <Template>
                  
                        <br />
                        <ig:WebTextEditor ID="WebTextEditor1" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor2" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor3" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor4" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor5" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor6" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor7" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor8" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor9" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor10" runat="server">
                        </ig:WebTextEditor>
                        <ig:WebTextEditor ID="WebTextEditor11" runat="server">
                  
                    </Template>
                </ig:ContentTabItem>
                <ig:ContentTabItem runat="server" Text="Tab 2">
                    <Template>
                    
                        <ig:WebMonthCalendar ID="WebMonthCalendar1" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar2" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar3" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar4" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar5" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar6" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar7" runat="server">
                        </ig:WebMonthCalendar>
                        <ig:WebMonthCalendar ID="WebMonthCalendar8" runat="server">
                        </ig:WebMonthCalendar>
                    </Template>
                </ig:ContentTabItem>
            </Tabs>
            <ContentPane>
                <RoundedBackground Enabled="True" />
            </ContentPane>
            <PostBackOptions EnableAjax="True" EnableLoadOnDemand="True" />
        </ig:WebTab>