WebView2 is rendering the page but the content is displayed all transparent

[alxdg]

Description
I am running into an issue where the web view is rendering the contents of my page but nothing is getting displayed on the container, it shows the contents all transparent, this behavior is only happening on a fresh installation of Windows.

I looked for errors in the developer console, program execution logs and event manager and there are no error reported anywhere.

This error only happens after deploying the app to other PCs, during development everything looks correct when I am running the app from Visual Studio.

Version
SDK: WebView 1.0.774.44
Runtime: Webview2 Fixed version 89.0.774.57
Framework: Webview1
OS: 10.0.19042 Build 19042

Screenshots
There is really nothing to show here only comment is that I can see that the images are getting rendered since I can drag them by clicking around and moving my mouse while holding down the click.

AB#32422186

[alxdg]

I was able to get passed this issue, I noticed that the AllowsTransparency="True" on the main window was the reason why everything was transparent, but now I am seeing the resize border and I am not able to hide this. Any suggestions?

[champnic]

Hey @alxdg - thanks for the feedback!

In the screenshot you included, what is the WebView2 and what is the host app drawing? Is the WebView2 now displaying correctly when you changed the AllowsTransparency property?

[FrunkQ]

I have experienced the exact same issue with a .NET Framework 4.7.2 application. I have had the opportunity to test on over a dozen machines. It works fine 90% of the time; the only machines that were failing contained “old or esoteric graphics hardware”:

2 machines with Intel Integrated Graphics from 2012 and an 8 output Matrox card (M9188).

Looks like those cards don’t handle transparency well. I tried turning off hardware acceleration but it made no difference RenderOptions.ProcessRenderMode = System.Windows.Interop.RenderMode.SoftwareOnly;

Ditching the Window Transparency as described above fixed the issue but the same ugly bar appeared at the top.

[champnic]

Thanks for confirming the repro. I'll add this bug on our backlog to take a look.

[RendijsSmukulis]

I wanted to add that we're seeing the same behavior in our app. Setting AllowsTransparency to true on the window that hosts the WebView2 control stops some parts of the WebView2 showing. E.g. it will show popups, but not the page content.

This can be easily repro'd in a Windows virtual machine running on Hyper-V, every single VM I have tried exhibits this behavior.

[champnic]

We have a known issue we're working on where VMs trigger us to use software rendering, which was causing some problems that look very similar to this. I'll let you know when we have a fix and we'll verify this case as well. @bradp0721 FYI

@alxdg When you are deploying to other PCs are you using VMs?

[alxdg]

When running VMs the result was always the same but in some instances of non VMs the problem persisted

[champnic]

@alxdg Sounds like it might be related then. On normal non-VM machines there are other cases that can trigger us to use software rendering, like specific graphics drivers, etc.

[alinarik]

I can confirm that I have the same problem with normal computers with an integrated Intel graphics card (Like Intel Q45). On these computers I have to set the AllowTransparency to false for the Webview to show up. On others computer with Nvidia graphic cards it shows up fine.
The only thing I don't understand is that my development computer doesn't have the problem even with an integrated Intel card (HD 520)

[OllieJones]

Same problem here. I have a demo based on the super-simple Getting Started app at https://docs.microsoft.com/en-us/microsoft-edge/webview2/ My reproduction of the problem is here. https://github.com/OllieJones/Webview2Win81Issue1118Demo

Everything works fine on Windows 10. I've tested it both on a physical machine and on a VM (VirtualBox).

On Windows 8.1 (VirtualBox VM based on modern.ie downloadable vms) the appearance of the website rendered in the WebView2 control is concealed behind the background color. Mouse events function normally though.

The workaround is obvious. Set the AllowTransparency attribute to False in this sample xaml.

<Window x:Class="Webview2Stripped.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Webview2Stripped"
        xmlns:wv2="clr-namespace:Microsoft.Web.WebView2.Wpf;assembly=Microsoft.Web.WebView2.Wpf"
        mc:Ignorable="d"
        Title="MainWindow" 
        Height="450"
        Width="800"
        Top="300"
        AllowsTransparency="True"
        WindowStyle="None"
        >

The problem also exists with an old modern.ie Windows 7 SP1 VirtualBox VM, for what it's worth.
I haven't tried it on any Windows Server releases.

And, just to make things wierder, on the offending systems when AllowsTransparency is false and Background is some color (like "red"), restoring the window from an iconized view paints over the rendered web site with the background. It's still there, it just can't be seen. Again, not a problem on W10, only on prior versions.

(We have lots of enterprise users dragging their feet migrating to Windows 10, so 8.1 is relevant to our business.)

[johna-ms]

@OllieJones I deployed your app on a modern.ie windows 8.1 virtualbox vm and it seems to load webview fine. I don't see the web content being obscured by the background color in any way. The only changes I made to the vm were downloading .NET runtime 478 and the webview2 runtime. Could you let me know if there are any other changes you made to your environment that I didn't? Also could you post a screenshot of the working/not working app so I know what to look for?

[johna-ms]

Just pinging this thread to see if anyone has any further info on a repro