Disabled Controls Inside ScrollViewer Consume Scroll Input Preventing Scrolling

[AVVI94]

Describe the bug

Issue Overview

When a disabled control (IsEnabled="False") is placed inside a ScrollViewer, it incorrectly intercepts and consumes mouse scroll input events, preventing the ScrollViewer from handling them as intended. This behavior occurs even if the disabled controls, such as a TextBlock or a TextBox, are not focusable and are not actively interacting with the user. The problem is evident when the mouse is positioned over these controls, and the user attempts to scroll the ScrollViewer.

Observed Behavior

• Scroll input is intercepted by the disabled controls, preventing the ScrollViewer from scrolling.
• The issue is observed with both focusable controls (e.g., TextBox) and non-focusable controls (e.g., TextBlock), indicating that the disabled state alone is causing the problem.
• The controls effectively "block" the scroll event, creating a poor user experience, as users cannot scroll when the cursor is positioned over disabled elements.

Problem occured after upgrading from Avalonia 11.0.10 to >= 11.1.0.

To Reproduce

1. Create a ScrollViewer with content that exceeds the viewport, allowing scrolling.
2. Inside the ScrollViewer, place a container (e.g., DockPanel) with IsEnabled="False".
3. Populate the disabled container with child elements such as TextBlock and TextBox.
4. Run the application and hover the mouse cursor over the disabled elements.
5. Attempt to scroll using the mouse wheel.

Expected behavior

• Mouse scroll events should propagate to the ScrollViewer, allowing scrolling regardless of whether the child controls are disabled.
• Disabled controls should not interfere with input event handling when they are visually non-interactive.

Avalonia version

>= 11.1.0

OS

Windows

Additional context

Tested with this XAML code:

<ScrollViewer>
    <DockPanel IsEnabled="False">
        <TextBlock Text="AAAAAAAAAAAAAAAAAAAA" DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 IsEnabled="False"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
        <TextBox Margin="0,10"
                 HorizontalAlignment="Stretch"
                 DockPanel.Dock="Top" />
    </DockPanel>
</ScrollViewer>