No Alex,

Even after changing that also it is not changing the background.

It is displaying default color ( white) only.

This is because of the Template of the TabItemEx. The Background color is bound to the Background property of a Border inside the Template. However, there is a button inside this border, which fills up the Border element and that is why you cannot see the Background changing. If you need to see that, you can retemplate the TabItemEx and change the way Background is set. You can of course find this style in the DefaultStyles directory

I am pasting a simple style for this:

<Style TargetType="{x:Type igWindows:TabItemEx}">

                <Setter Property="Template">

                    <Setter.Value>

                        <ControlTemplate TargetType="{x:Type igWindows:TabItemEx}">

                            <Grid SnapsToDevicePixels="true">

                                <Border

Name="Bd"

                                    Background="{TemplateBinding Background}"

Padding="{TemplateBinding Padding}"

BorderBrush="{TemplateBinding BorderBrush}"

BorderThickness="1,1,1,0"

CornerRadius="3,3,0,0">

                                    <Grid>

                                        <Grid.ColumnDefinitions>

                                            <ColumnDefinition/>

                                            <ColumnDefinition Width="Auto"/>

                                        </Grid.ColumnDefinitions>

                                        <ContentPresenter

Name="Content"

ContentSource="Header"

SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"

RecognizesAccessKey="true"

HorizontalAlignment="{Binding Path=HorizontalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"

VerticalAlignment="{Binding Path=VerticalContentAlignment, RelativeSource={RelativeSource AncestorType={x:Type ItemsControl}}}"/>

                                        <Button

Name="CloseButton"

Grid.Column="1"

Command="igWindows:TabItemExCommands.Close"

CommandTarget="{Binding RelativeSource={RelativeSource TemplatedParent}}"

Visibility="{TemplateBinding ComputedCloseButtonVisibility}" 

Style="{DynamicResource {x:Static igWindows:XamTabControl.CloseButtonStyleKey}}"

Margin="10,0,0,0"

/>

                                    </Grid>

                                </Border>

                            </Grid>

                        </ControlTemplate>

                    </Setter.Value>

                </Setter>

                <Style.Triggers>

                    <Trigger Property="IsMouseOver" Value="True">

                        <Setter Property="Background" Value="Green"></Setter>

                        <Setter Property="Foreground" Value="Green"></Setter>

                    </Trigger>

                    <Trigger Property="IsSelected" Value="True">

                        <Setter Property="Background" Value="Red"/>

                        <Setter Property="Foreground" Value="Red"/>

                    </Trigger>

                </Style.Triggers>

            </Style>