Render bug when visibility changes

[Wupval]

Hi, we found a bug when using CefSharp for WPF.
When there are multiple browser instances (in our case it starts to bug when there are 6), and a browser goes invisible and visible again, it stops rendering.
For example, when 6 browsers all display the google.com site and the visibility gets toggled off and on, then it is impossible to scroll or click, no animations, etc.
Interestingly, the cursor still changes according to the frozen site and the tooltips also work.

This happens in Nuget CefSharp.Wpf.NETCore version 106.0.260 for x64, but we traced it back to when we upgraded from 93.1.140 to 94.4.20
OS is Windows 10, x64
.NET 6.0, also happens in .NET 5.0

Generally, we noticed it when having only 4 browsers with their Dev-Tools open. After some testing in the Minimal Example, I realised it also happens when there are many browser instances.
I would have reported it as an issue, but I don't actually know if it is a CefSharp bug or a Cef bug and I don't know how to recreate it in C++

If you want to recreate the bug yourself, the files of the example are attached (Just copy paste into the minimal example).
Just start the app, wait for the instances to finish being created, toggle the visibility of the first browser with the button in top right.
example_files.zip

[amaitland]

Likely a CEF issue.

https://bitbucket.org/chromiumembedded/cef/issues/2483/osr-invalidate-does-not-generate-frame

[Wupval]

Which way would you prefer to have it tested?

[amaitland]

As it sounds like it works then next step will be to port the commit to target master. PRs welcome.

It's probably also worth creating an new issue on CEF Issue Tracker. The original issue is marked as resolved. Make sure the issue actually gets fixed.

[Wupval]

Pull request is created #4307
I'll look into creating a new issue for CEF, but this will take some time

[mayphi]

Cef Issue: chromiumembedded/cef#3427

[jingtao01]

Likely a CEF issue.

https://bitbucket.org/chromiumembedded/cef/issues/2483/osr-invalidate-does-not-generate-frame

Also happened here.
And I found that calling browser.GetHost().NotifyScreenInfoChanged() in ChromiumWebBrowser::OnBrowserWasHidden when hidden is false can fix this instead of thre resize hack, because I might change size later.
Just FYI.