[Bug] ResizeObserver loop completed with undelivered notifications.

Reproducible in vscode.dev or in VS Code Desktop?

• Not reproducible in vscode.dev or VS Code Desktop

Reproducible in the monaco editor playground?

• Not reproducible in the monaco editor playground

Monaco Editor Playground Link

No response

Monaco Editor Playground Code

No response

Reproduction Steps

I initialize an editor in WebView2 using the following:

        const options: monaco.editor.IStandaloneEditorConstructionOptions = {
            value: 'test',
            language: 'csharp',
            theme: 'vs-dark',
            automaticLayout: true,
            contextmenu: false,
            minimap: { enabled: false },
            scrollBeyondLastLine: false,
        };

I place the editor inside a resizable div and try to resize it. The console spews errors:

ResizeObserver loop completed with undelivered notifications.

Here's some pseudo-code for the html/style:

<div class="resizable">
    <div class="code-editor" bind:this={container}></div>
</div>

<style>
    .code-editor {
        width: 100%;
        height: 100%;
    }
    .resizable {
        overflow: auto;
        height: var(--me-default-height);
        resize: vertical;
    }
</style>

Actual (Problematic) Behavior

Resizing monaco-editor spams the console with errors. It only happens when the editor is being shrunk, not when it's being expanded.

Expected Behavior

I would expect no errors when resizing monaco editor.

Additional Context

This is all using WebView2.

Start by reproducing issue #4333 in WebView2 with automaticLayout enabled, using the provided resizable container and editor options, then compare shrinking and expanding behavior. Trace the resize handling and ResizeObserver notifications; done means resizing the editor no longer produces “ResizeObserver loop completed with undelivered notifications.”