Transparent fullscreen window blocks clicks in Avalonia (works in WPF)

[nam1403]

In my WPF project I have:

<Window
    Title=""
    AllowsTransparency="True"
    Background="Transparent"
    WindowStyle="None"
    Topmost="True"
    WindowState="Maximized">

    <Grid>
        <Button Content="Click Me"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"/>
    </Grid>
</Window>

With WPF, this window is transparent and I can easily click through to the applications underneath, while the button in the window is still clickable.

However, when I try to do the same thing in Avalonia, it does not work.

My Avalonia window:

<Window
    Title=""
    TransparencyLevelHint="Transparent"
    ExtendClientAreaToDecorationsHint="True"
    ExtendClientAreaChromeHints="NoChrome"
    ExtendClientAreaTitleBarHeightHint="-1"
    TransparencyBackgroundFallback="Transparent"
    Background="{x:Null}"
    SystemDecorations="None"
    Topmost="True"
    WindowState="Maximized">

    <Grid>
        <Button Content="Click Me"
                HorizontalAlignment="Center"
                VerticalAlignment="Center"/>
    </Grid>
</Window>

In Avalonia, the window becomes transparent visually, but it still blocks mouse input, so I cannot click the applications underneath.

I have tried many approaches (searching online, suggestions from ChatGPT, etc.), but none of them worked.

Does anyone know why this works in WPF but not in Avalonia, and if there is a way to achieve the same behavior in Avalonia?

[LaurentInSeattle]

Edit:
NVM: I missed the "Background="{x:Null}" in the aXAML

---

In Avalonia, Transparent and no background are different regarding mouse hits:

No Background => No hits
Transparent => Get hits

[timunie]

This is a known limitation which no one had time to fix yet

[theoractice]

Can't you do that with win32 api? SetWindowLong etc.

[thevortexcloud]

You need to manually do it yourself as far as I am aware.

#17836