'ToolTip' cannot have a logical or visual parent

Question

I have the following problem. I keep getting 'ToolTip' cannot have a logical or visual parent error when i try to style tooltip for the toggle button. What went wrong? When i take out the tooltip control under ToggleButton.ToolTip it works !

 <ToggleButton x:Name="toggle" OverridesDefaultStyle="True" Template="{StaticResource ExpanderToggleButton}" Margin="0,4,0,0" VerticalAlignment="Top" IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}">
     <ToggleButton.ToolTip>
         <ToolTip Style="{StaticResource tooltipstyle}">                        
             <TextBlock Background="Transparent"/>                                                                                                                      
         </ToolTip>
     </ToggleButton.ToolTip>
 </ToggleButton>

Answer 1

If you write code like this using property element syntax, you call already the constructor of the ToolTip class.

<ToggleButton.ToolTip>
    <TextBlock></TextBlock>                                                 
</ToggleButton.ToolTip>

There is no need to instantiate another ToolTip inside like this...

 <ToggleButton.ToolTip>
     <ToolTip Style="{StaticResource tooltipstyle}">                        
         <TextBlock Background="Transparent"/>                                                                                                                      
     </ToolTip>
 </ToggleButton.ToolTip>

Besides, on my system (using .NET 4.5) there is no error. It seems that WPF can handle both versions meanwhile as intended by the developer.