Question

I’m using the ExpressionDark theme for my WPF app, it has a custom style for MenuItems.
When a MenuItem is disabled it should use a gray style to reflect this, and it works for MenuItems inside the Menu control:

It does however not work for MenuItems that are in a ContextMenu (Copy is disabled)

I have tracked down the problem to the TextBlock style, if I remove this style it works for the ContextMenu, but other styles break with it removed

<Style TargetType="{x:Type TextBlock}">
    <Setter Property="Foreground" Value="{DynamicResource TextBrush}" />
</Style>

EDIT: It doesn’t matter if I use a MenuItem or my custom GestureMenuItem, but what do matter is if i use a _ char or not (For key shortcuts) If I remove _ then the style wont work in MainMenu either.

The relevant style for the MenuItem:

<Trigger Property="IsEnabled" Value="false">
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
</Trigger>

Source code found here. The relevant ContextMenu XAML:

<TextBox x:Name="Text"
    Height="Auto"
    TextWrapping="Wrap"
    VerticalScrollBarVisibility="Visible"
    AcceptsReturn="True"
    IsReadOnly="true">
    <TextBox.ContextMenu>
        <ContextMenu>
            <MenuItem Header="Copy" Command="Copy">
                <MenuItem.Icon>
                    <Image Source="{StaticResource IconCopy}"/>
                </MenuItem.Icon>
            </MenuItem>
            <Separator></Separator>
            <MenuItem cal:Message.Attach="Clear()" Header="Clear All">
                <MenuItem.Icon>
                    <Image Source="{StaticResource IconDelete}"/>
                </MenuItem.Icon>
            </MenuItem>
        </ContextMenu>
    </TextBox.ContextMenu>
</TextBox>

MenuItems in working main menu (GestureMenuItem inherits MenuItem and uses same style):

<Menu IsMainMenu="True">
    <Menu.Resources>
        <Image x:Key="ViewIcon" x:Shared="false"
            Source="{Binding Path=Icon}" />
    </Menu.Resources>
    <!-- Items here removed to shorten XAML -->
    <MenuItem Header="_Script">
        <common:GestureMenuItem x:Name="RunScript" Header="_Run script" Key="F5">
            <MenuItem.Icon>
                <Image Source="{StaticResource IconPlay}"/>
            </MenuItem.Icon>
        </common:GestureMenuItem>
      <common:GestureMenuItem x:Name="StopScript" Header="_Stop script" Key="F5" Modifiers="Shift">
            <MenuItem.Icon>
                <Image Source="{StaticResource IconStop}"/>
            </MenuItem.Icon>
        </common:GestureMenuItem>
    </MenuItem>
    <!-- Items here removed to shorten XAML -->
</Menu>

Gesture item style:

<Style TargetType="{x:Type Caliburn:GestureMenuItem}" BasedOn="{StaticResource {x:Type MenuItem}}">
</Style>

I came up with a work around, it wont give the exact same style, but it works, should I go for it?

<Trigger Property="IsEnabled" Value="False">
    <Setter Property="Opacity" Value="0.5"/>
</Trigger>

Both gesture text and icon is gray with this solution so maybe it a actually a better solution than just setting Forecolor to gray:

Answer 1

I solved it by replacing the Forecolor property setter with a Opacity property setter, this will also effect gesture text and icon which is also the default style’s way of doing it

<Trigger Property="IsEnabled" Value="False">
    <Setter Property="Opacity" Value="0.3"/>
</Trigger>