ToolTip is not showing in WPF Label?

Question

In application, I am trying to set a Tool-tip on Label control. Please find the detail XAML, suggest to fix the issue if possible. So far i have tried many tricks (e.g IsEnabled, IsHitTestVisible, control template, background setting...), but failed to display tooltip.

<UserControl x:Class="HSDLAdminPortal.Forms.Application.ApplicationDetailForm"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:toolkit="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Layout.Toolkit"             
         xmlns:local="clr-namespace:HSDLAdminPortal.Forms.Application"
         mc:Ignorable="d" Width="1290" Height="595"
         xmlns:gif="http://wpfanimatedgif.codeplex.com"              
         xmlns:name="UserControl"
         >
<UserControl.Resources>
    <Style x:Key="LabelInfoStyle" TargetType="{x:Type Label}">
        <Setter Property="FontSize" Value="12"/>
        <Setter Property="Foreground" Value="Black"/>
    </Style>
    <Style x:Key="LabelInfoValueStyle" TargetType="{x:Type Label}">
        <Setter Property="FontSize" Value="12"/>
        <Setter Property="Foreground" Value="#999966"/>
    </Style>
    <Style x:Key="LabelInfoHeaderStyle" TargetType="{x:Type Label}">
        <Setter Property="FontSize" Value="14"/>
        <Setter Property="Foreground" Value="White"/>
    </Style>
</UserControl.Resources>
<Grid Margin="4" Background="Transparent">
    <Grid.Background>
        <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
            <GradientStop Color="#e6eeff" Offset="1" />
            <GradientStop Color="#FFF5F2EF" Offset="0" />
        </LinearGradientBrush>
    </Grid.Background>
    <Grid.Resources>
        <ResourceDictionary Source="/Resources/CustomAccordion.xaml"/>
    </Grid.Resources>
    <Grid.RowDefinitions>
        <RowDefinition Height="*" />
        <RowDefinition Height="auto" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="auto" />
        <ColumnDefinition Width="*" />
    </Grid.ColumnDefinitions>
    <Grid Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2" Margin="0,-10,730,0" Background="Transparent" Panel.ZIndex="1">
        <Grid.RowDefinitions>
            <RowDefinition Height="*" />
            <RowDefinition Height="auto" />
        </Grid.RowDefinitions>
        <StackPanel>
            <GroupBox Header=""  Margin="0,4,10,4" Height="540" HorizontalAlignment="Right" Width="532">
                <Canvas Margin="0,0,0,1">
                    <Rectangle HorizontalAlignment="Left" Height="19" Stroke="White" VerticalAlignment="Top" Width="493" Canvas.Left="17" Canvas.Top="201">
                        <Rectangle.Fill>
                            <LinearGradientBrush  EndPoint="0.5,1" StartPoint="0.5,0">
                                <GradientStop Color="LightGray" Offset="1" />
                                <GradientStop Color="LightGray" />
                                <GradientStop Color="White" Offset="0.5" />
                            </LinearGradientBrush>
                        </Rectangle.Fill>
                    </Rectangle>
                    <Rectangle Fill="Transparent" HorizontalAlignment="Left" Height="295" Stroke="Gray" VerticalAlignment="Top" Width="493" Canvas.Left="17" Canvas.Top="219"/>
                    <Image Stretch="Fill"  x:Name="ImagePhoto" HorizontalAlignment="Left" VerticalAlignment="Top" Height="123"  Width="120" Source="/HSDLAdminPortal;component/Resources/photo_test.png" Canvas.Top="3" Canvas.Left="37"/>
                    <Label x:Name="LblPhoto" Content="Photo" HorizontalAlignment="Left" Background="Transparent"  VerticalAlignment="Top" FontSize="10" FontWeight="Bold" Height="22" Width="62" Canvas.Top="124" Canvas.Left="75"/>
                    <Border BorderBrush="Black" BorderThickness="1" Height="128" Canvas.Left="37" Canvas.Top="1" Width="119"/>
                    <Rectangle Height="22" Canvas.Left="221"  Canvas.Top="1" Width="289">
                        <Rectangle.Fill>
                            <LinearGradientBrush  EndPoint="0.5,1" StartPoint="0.5,0">
                                <GradientStop Color="LightGray" Offset="1" />
                                <GradientStop Color="LightGray" />
                                <GradientStop Color="White" Offset="0.5" />
                            </LinearGradientBrush>
                        </Rectangle.Fill>
                    </Rectangle>
                    <Rectangle Fill="Transparent" HorizontalAlignment="Left" Height="163" Stroke="White" VerticalAlignment="Top" Width="289" Canvas.Left="221" Canvas.Top="23"/>
                    <Label x:Name="LblMiscellaneous" Style="{DynamicResource LabelInfoHeaderStyle}" Foreground="Black" Content="Miscellaneous" Background="Transparent" Canvas.Left="342" Canvas.Top="-1" Height="28" FontWeight="ExtraBold"/>
                    <Label x:Name="LblPersonalInfo" Style="{DynamicResource LabelInfoHeaderStyle}" Content="Personal Info" Foreground="Black" Background="Transparent" Canvas.Left="221" Canvas.Top="195" Height="54" Width="125" FontWeight="ExtraBold"/>

                    <Label x:Name="LblApplicantType" ToolTip="text tooltip" Style="{DynamicResource LabelInfoStyle}" Content="Applicant Type : " Background="Transparent" Canvas.Left="231" Canvas.Top="40" FontWeight="Bold"/>
                    <Label x:Name="LblApplicantTypeValue" Style="{DynamicResource LabelInfoValueStyle}" Content="N/A" Background="Transparent" Canvas.Left="360" Canvas.Top="40"  FontWeight="Bold"/>

                    <Label x:Name="LblApplicantNameValue" Style="{DynamicResource LabelInfoValueStyle}" ToolTip="Sample ToolTip" Content="N/A" ToolTip="Sample ToolTip" Background="Transparent" Canvas.Left="190" Canvas.Top="220"  FontWeight="Bold"/>
                    <Image x:Name="ImageSignature" HorizontalAlignment="Left" VerticalAlignment="Top" Height="37"  Width="97" Source="/HSDLAdminPortal;component/Resources/signature.png" Canvas.Top="149" Canvas.Left="52"/>
                    <Border BorderBrush="Black" BorderThickness="1" Height="44" Canvas.Left="37" Canvas.Top="142" Width="119"/>
                    <Label x:Name="LblSignature" Content="Signature" HorizontalAlignment="Left" Background="Transparent"  VerticalAlignment="Top" FontSize="10" FontWeight="Bold" Height="36" Width="62" Canvas.Top="181" Canvas.Left="69"/>
                    <Canvas x:Name="AttachmentDetailsCanvas" Width="520" Height="501"  Visibility="Visible" Opacity="0">
                        <Canvas.Background>
                            <LinearGradientBrush  EndPoint="0.5,1" StartPoint="0.5,0">
                                <GradientStop Color="LightGray" Offset="1" />
                                <GradientStop Color="LightGray" />
                                <GradientStop Color="White" Offset="0.5" />
                            </LinearGradientBrush>

                        </Canvas.Background>

                        <Rectangle Height="45" Canvas.Left="0"  Canvas.Top="1" Width="520">
                            <Rectangle.Fill>
                                <LinearGradientBrush  EndPoint="0.5,1" StartPoint="0.5,0">
                                    <GradientStop Color="LightGray" Offset="1.2" />
                                    <GradientStop Color="LightGray" />
                                    <GradientStop Color="#0077b3" Offset="0" />
                                </LinearGradientBrush>
                            </Rectangle.Fill>
                        </Rectangle>
                        <Label x:Name="attachmentDetails" Content="Attachment Details" Foreground="White"  Background="Transparent" FontSize="20"  VerticalAlignment="Top"  FontWeight="Bold" Height="36" Width="220" Canvas.Top="4" Canvas.Left="143" />

                        <Image Source="/Resources/Images/attachment.png" Height="400" Width="510" Canvas.Top="86" x:Name="atcImg"/>
                        <Button ToolTip="Click To Hide Image" x:Name="hideImageButtonButton" Width="42" Height="42" Click="hideImageButton_Click" Canvas.Left="478" Canvas.Top="1">
                            <StackPanel Orientation="Horizontal">
                                <Image x:Name="close_image" HorizontalAlignment="Center" VerticalAlignment="Center" Source="/Resources/hide.png" Height="42" Width="42" OpacityMask="{DynamicResource {x:Static SystemColors.WindowBrushKey}}" Stretch="UniformToFill" />
                            </StackPanel>
                        </Button>
                    </Canvas>
                </Canvas>
            </GroupBox>
        </StackPanel>
    </Grid>

</Grid>

Answer 1

Explicit style. The Style property is set directly. In most scenarios, the style is not defined inline, but instead is referenced as a resource, by explicit key. In this case the Style property itself acts as if it were a local value, precedence item 3.

MSDN website on precedence.

As the Style is set as a local value it takes precedence over the next local value.

Add Tooltip to your style and add the text you want there for it to work with your dynamic resource

UPDATE

After looking at your code, it is clear that your label is just covered by a transparent grid, so your mouseover never really goes over it. Put, Panel.ZIndex="1" and it will work as this brings your label in front of everything

I would also look at the MSDN website, if you plan on using more than one zindex to overcome your problem, just to learn more about it.

https://msdn.microsoft.com/en-us/library/system.windows.controls.panel.zindex(v=vs.110).aspx

  <Label x:Name="LblApplicantNameValue" Panel.ZIndex="1" Style="{DynamicResource LabelInfoValueStyle}" ToolTip="Sample ToolTip" Content="this label now works"  Background="Transparent" Canvas.Left="360" Canvas.Top="66"  FontWeight="Bold"/>