Issue Description

We will see a gray screen in WebView2 when we do not use the application for a long time. We can easily reproduce the issue with Webview2 sample.

1. Download and compile the sample in WebView2WpfBrowser
2. Run the WebView2WpfBrowser.exe and change the resolution or Scale in Settings–>System–> Display –> Scale&Layout.
3. Click “Window –> New WebView” in the menu of WebView2WpfBrowser.exe
4. Instead of displaying HTML content, WebView2WpfBrowser.exe only shows the background of EdgeWebView2-80.jpg.

Troubleshooting

Try to reproduce the issue.

1. Notice that the process and windows change during the issue. The behavior is observed when working with a single display RDP session after coming home.
2. Noticed the window resize event every time when we reproduced the issue.
3. We can always reproduce the issue when we reconnect RDP session from multiple displays to single displays.
4. After adding DPI Awareness code following Setting the default DPI awareness for a process (Windows), the issue is gone.

Cause

The scenario is a unique one that only occurs for System awareness.

Previously, the system DPI was fixed when the user logged on and never changed. But new Windows feature added support for setting current monitors DPI as system DPI for app when the app is launched.

The root cause of this issue is application launch with a system DPI, before creating WebView2 we changed system DPI (with the operation of dock/undock, RDP, or change display settings) , then new created WebView2 will get a new system DPI (different with application DPI).

Because DPI does not match, the WebView2 does not render any of the content.

Resolution

1.Use PerMonitorV2 DPI awareness mode.

• Win32: Setting the default DPI awareness for a process (Windows)

• WPF: WPF-Samples/readme.md at main · microsoft/WPF-Samples (github.com)

• Winform: High DPI support - Windows Forms .NET Framework

2.Use the PERPROCESSSYSTEMDPIFORCEOFF AppCompatFlag

• Find the application .exe and right click on it and select properties
• Click on the Compatibility tab
• Click on the Change high DPI setting button
• Under Program DPI, select the Use this setting to fix scaling problems for this program instead of the one in Settings
• From the Use the DPI that’s set for my main display when: I signed into Windows
• Click the OK button to save these changes

This will create a new registry String Value under below registry path which containing the the path to the application executable.:

HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers