input cannot focus when switching webview

[roguexiaohuihui]

Issue Type: Bug
I created a webview with just an input tag in it, and I just asked input.focus()

1、The first time you open the webview you can focus properly

2、Switch to another document or webview

3、So let's go back to the first step, the webview，the focus is gone，just click the mouse down the webview and the focus will work

VS Code version: Code 1.39.0
OS version: Windows10

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Does not restore webview focus when switching back to VS Code window (#72525)
• Support WebViews in extension contributed custom views (#83911)
• Command Palette should steal focus from active webview... (#62403)
• ctrl+w is closing 2 editors when custom webview editor image preview is focused (#81771)
• Try better webview focus tracking solution in Electron 6+ (#65413)

[mjbvz]

I can't repo in the current insiders builds (1.41). Please share the example extension

[roguexiaohuihui]

I can't repo in the current insiders builds (1.41). Please share the example extension

I created a simple demo, modified with webview official instance, please help to look at this problem：
https://github.com/roguexiaohuihui/input-focus

[roguexiaohuihui]

when switching webview, the plug-in transmits a signal to webview through message and actively asks the input of webview to focus again. Instead of the input being focused after the mouse click on the screen

[roguexiaohuihui]

@mjbvz I hope you can take a look at this problem when you are free

[mjbvz]

There are are few different issues here:

• The example extension calls this._update(); which reload the webview every time the focus changes.

• However even if you fix that, the bug still exists.

• I then pushed a fix for this issue (2815e73), but that fix only work with iframe based webveiews

• It is not fixed for normal electron based webviews. The root problem is that we see the following sequence of actions when switching focus:

  • The extension's focus message is received by the extension's JS
  • This focuses the input element
  • Our host.onMessage('focus', () => { event handler is then invoked
  • At this point, the document.activeElement is now pointing to the wrong element (it's not on the input element anymore).

Since this works fine with iframe based webviews, I assume there is some weird electron specific behavior going on here. I can't track down who is setting the focus here between the extension code running and host.onMessage running

I'm going to close this issue since we have not seen many other reports of it. Hopefully it will be fully fixed on desktop VS Code by #83188