src/vs/workbench/browser/parts/editor/textDiffEditor.ts/TextDiffEditor/updateReadonly
class TextDiffEditor:	protected override updateReadonly(input: EditorInput): void {
		if (input instanceof DiffEditorInput) {
			this.diffEditorControl?.updateOptions({
				readOnly: input.hasCapability(EditorInputCapabilities.Readonly),
				originalEditable: !input.original.hasCapability(EditorInputCapabilities.Readonly),
			});
		} else {
			super.updateReadonly(input);
		}
	}