New Post: CheckComboBox - ItemTemplate

<CheckBox Grid.Column="0" Content ="{TemplateBinding Content}"  ... />
<ContentPresenter Grid.Column="1" Content="{TemplateBinding Content}" ... />

<TextBlock Text="{TemplateBinding ContentPresenter.Content}" .../>

<TextBlock Text="{Binding Content, RelativeSource={RelativeSource TemplatedParent}}" .../>