Make telemetry always reflect UI (#15547)

src/vs/platform/telemetry/common/telemetry.ts

@@ -80,7 +80,7 @@ export function loadExperiments(storageService: IStorageService, configurationSe
 
 	const random0 = parseFloat(valueString);
 	let [random1, showDefaultViewlet] = splitRandom(random0);
-	const [random2, showFirstSessionWatermark] = splitRandom(random1);
+	let [random2, showFirstSessionWatermark] = splitRandom(random1);
 	let [, openUntitledFile] = splitRandom(random2);
 
 	// is the user a first time user?
@@ -88,6 +88,7 @@ export function loadExperiments(storageService: IStorageService, configurationSe
 	if (!isNewSession) {
 		// for returning users we fall back to the default configuration for the sidebar and the initially opened, empty editor
 		showDefaultViewlet = defaultExperiments.showDefaultViewlet;
+		showFirstSessionWatermark = defaultExperiments.showFirstSessionWatermark;
 		openUntitledFile = defaultExperiments.openUntitledFile;
 	}