[Bug] Incorrect CSS causes repaint with every caret blink

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

Enable "Paint Flashing" in Chrome dev tools (tested with Chrome 126.0.6478.127 on macOS 14.2.1 (23C71)).

In some cases, the dev tools paint reflash doesn't work for the embedded iframe in playground. However, the broken repaint on caret blink should still be observable in the editor on the left

Actual (Problematic) Behavior

• Try any monaco version after the referenced CSS change, including the latest one (0.50.0) and observe the entire editor repaint with each caret blink

https://github.com/user-attachments/assets/e53de4d1-e800-474c-9e52-ed600700e10c

Expected Behavior

• Try again with a version before the referenced CSS change (eg: 0.43.0) and notice only the caret re-paints.

https://github.com/user-attachments/assets/d77c1383-5881-4a81-bd4e-d6e397237360

Additional Context

The CSS block here seems to be incorrect: https://github.com/microsoft/vscode/blob/1.91.1/src/vs/editor/standalone/browser/standalone-tokens.css#L40-L55

Presumably all the .monaco-editor, .monaco-diff-editor <foo> rules should instead be .monaco-editor <foo>, .monaco-diff-editor <foo>

As a side-effect, this change appears to cause the repaint on every caret blink as described above.

Inspect src/vs/editor/standalone/browser/standalone-tokens.css around lines 40-55, then reproduce the issue with Chrome DevTools Paint Flashing using a recent Monaco version and compare with 0.43.0. Done means the CSS selectors no longer trigger a full editor repaint on each caret blink, with only the caret repainting.