workaround for #52196

src/vs/editor/browser/services/codeEditorServiceImpl.ts

@@ -212,7 +212,7 @@ class DecorationTypeOptionsProvider implements IModelDecorationOptionsProvider {
 
 const _CSS_MAP: { [prop: string]: string; } = {
 	color: 'color:{0} !important;',
-	opacity: 'opacity:{0};',
+	opacity: 'opacity:{0}; will-change: opacity;',
 	backgroundColor: 'background-color:{0};',
 
 	outline: 'outline:{0};',

src/vs/editor/browser/widget/codeEditorWidget.ts

@@ -1805,7 +1805,7 @@ registerThemingParticipant((theme, collector) => {
 
 	const unnecessaryForeground = theme.getColor(editorUnnecessaryCodeOpacity);
 	if (unnecessaryForeground) {
-		collector.addRule(`.${SHOW_UNUSED_ENABLED_CLASS} .monaco-editor .${ClassName.EditorUnnecessaryInlineDecoration} { opacity: ${unnecessaryForeground.rgba.a}; }`);
+		collector.addRule(`.${SHOW_UNUSED_ENABLED_CLASS} .monaco-editor .${ClassName.EditorUnnecessaryInlineDecoration} { opacity: ${unnecessaryForeground.rgba.a}; will-change: opacity; }`);
 	}
 
 	const unnecessaryBorder = theme.getColor(editorUnnecessaryCodeBorder);