The Popup window Page didn't loaded #5112

ArunPandianRNT · 2025-05-21T11:58:24Z

ArunPandianRNT
May 21, 2025

Is there an existing issue for this?

I have searched both open/closed issues, no issue already exists.

CefSharp Version

135.0.220.0

Operating System

Windows 11

Architecture

AnyCPU

.Net Version

.NET 4.8

Implementation

WPF

Reproduction Steps

Load a webpage that includes a window.open() call or .

Observe that:

The popup may not appear at all.

If it appears, it may render blank or crash.

DevTools or modal dialogs may behave inconsistently.

Expected behavior

Popup windows should open in a new ChromiumWebBrowser instance or new WPF window.
The content should render as expected.

Actual behavior

Popup windows are either:

Not opening at all.

Appearing with no content.

Causing UI freezes or crashes.

Regression?

No response

Known Workarounds

No response

Does this problem also occur in the CEF Sample Application

Yes using WPF/OffScreen command line args

Other information

No response

amaitland · 2025-05-25T02:29:34Z

amaitland
May 25, 2025
Maintainer

Converting to discussion as this is fairly unlikely a bug in CefSharp directly.

135.0.220.0

Please confirm your issue reproduces with the current supported version, M136 at time of writing.

Load a webpage that includes a window.open()

Testing with https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_win_open using https://github.com/cefsharp/CefSharp.MinimalExample and it behaves as expected.

If it appears, it may render blank or crash.

You should check the log file for errors.

Expected behavior
Popup windows should open in a new ChromiumWebBrowser instance or new WPF window. The content should render as expected.

The default expected behavior would be to open in a new native window.

Does this problem also occur in the CEF Sample Application
Yes using WPF/OffScreen command line args

Did you actually test with the CEF Sample application? If not then please do so.

0 replies

arnoldleung · 2026-09-03T23:04:15Z

arnoldleung
Sep 3, 2026

This appears to be an issue with 151.3.170 Winforms also. I have used MinimalExample build (on 4.8 framework) on Winforms to test.

Running the default code works with clicking on button for the following:

https://www.w3schools.com/jsref/tryit.asp?filename=tryjsref_win_open

However, if the code is adjusted to run the window.open onload, it does not work. Only the button version works:

<!DOCTYPE html>
<html>
<body onload="myFunction()">

<h1>The Window Object</h1>
<h2>The open() Method</h2>

<p>Click the button to open a new browser window.</p>

<button onclick="myFunction()">Try it</button>

<script>
function myFunction() {
  window.open("https://www.w3schools.com",'test','left=75,top=5,width=650,height=535,resizable=0,scrollbars=0,menubar=0,status=0');
}
</script>

</body>
</html>

The above code have been tested with Chrome (v. 152) and Firefox (v. 155) and work as expected (ie: window pops up)

In my code, OnBeforePopup does not get triggered with the above code.

0 replies

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The Popup window Page didn't loaded #5112

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ArunPandianRNT May 21, 2025

Is there an existing issue for this?

CefSharp Version

Operating System

Architecture

.Net Version

Implementation

Reproduction Steps

Expected behavior

Actual behavior

Regression?

Known Workarounds

Does this problem also occur in the CEF Sample Application

Other information

Replies: 2 comments

Uh oh!

amaitland May 25, 2025 Maintainer

Uh oh!

arnoldleung Sep 3, 2026

ArunPandianRNT
May 21, 2025

amaitland
May 25, 2025
Maintainer

arnoldleung
Sep 3, 2026