chore: sync the change to net 40.

src/Net_40/HandyControl_Net_40/Themes/Styles/Base/CheckComboBoxBaseStyle.xaml

@@ -9,6 +9,7 @@
     <Style x:Key="Tag4CheckComboBoxStyle" BasedOn="{StaticResource TagBaseStyle}" TargetType="hc:Tag">
         <Setter Property="Padding" Value="6,2,4,2" />
         <Setter Property="Height" Value="Auto" />
+        <Setter Property="ShowCloseButton" Value="True" />
         <Setter Property="Template">
             <Setter.Value>
                 <ControlTemplate TargetType="hc:Tag">

src/Net_40/HandyControl_Net_40/Themes/Theme.xaml

@@ -7270,6 +7270,7 @@
 	<Style x:Key="Tag4CheckComboBoxStyle" BasedOn="{StaticResource TagBaseStyle}" TargetType="hc:Tag">
 		<Setter Property="Padding" Value="6,2,4,2" />
 		<Setter Property="Height" Value="Auto" />
+		<Setter Property="ShowCloseButton" Value="True" />
 		<Setter Property="Template">
 			<Setter.Value>
 				<ControlTemplate TargetType="hc:Tag">
@@ -14364,4 +14365,4 @@
 	</Style>
 	<Style BasedOn="{StaticResource RangeSliderBaseStyle}" TargetType="hc:RangeSlider" />
 	<Style BasedOn="{StaticResource SliderBaseStyle}" TargetType="Slider" />
-</ResourceDictionary>
+</ResourceDictionary>

src/Shared/HandyControl_Shared/Themes/Theme.xaml

@@ -7354,6 +7354,7 @@
 	<Style x:Key="Tag4CheckComboBoxStyle" BasedOn="{StaticResource TagBaseStyle}" TargetType="hc:Tag">
 		<Setter Property="Padding" Value="6,2,4,2" />
 		<Setter Property="Height" Value="Auto" />
+		<Setter Property="ShowCloseButton" Value="True" />
 		<Setter Property="Template">
 			<Setter.Value>
 				<ControlTemplate TargetType="hc:Tag">