diff --git a/packages/playwright-test/src/runner/uiMode.ts b/packages/playwright-test/src/runner/uiMode.ts
index 693d5c5aad..28bf7187d7 100644
--- a/packages/playwright-test/src/runner/uiMode.ts
+++ b/packages/playwright-test/src/runner/uiMode.ts
@@ -51,7 +51,7 @@ class UIMode {
     for (const p of config.projects)
       p.retries = 0;
     config._internal.configCLIOverrides.use = config._internal.configCLIOverrides.use || {};
-    config._internal.configCLIOverrides.use.trace = 'on';
+    config._internal.configCLIOverrides.use.trace = { mode: 'on', sources: false };
 
     this._originalStderr = process.stderr.write.bind(process.stderr);
     process.stdout.write = (chunk: string | Buffer) => {
diff --git a/packages/trace-viewer/src/ui/sourceTab.tsx b/packages/trace-viewer/src/ui/sourceTab.tsx
index cca9e06222..248dd2ebef 100644
--- a/packages/trace-viewer/src/ui/sourceTab.tsx
+++ b/packages/trace-viewer/src/ui/sourceTab.tsx
@@ -55,7 +55,14 @@ export const SourceTab: React.FunctionComponent<{
       return '';
     if (!stackInfo.fileContent.has(filePath)) {
       const sha1 = await calculateSha1(filePath);
-      stackInfo.fileContent.set(filePath, await fetch(`sha1/src@${sha1}.txt`).then(response => response.text()).catch(() => `<Unable to read "${filePath}">`));
+      try {
+        let response = await fetch(`sha1/src@${sha1}.txt`);
+        if (response.status === 404)
+          response = await fetch(`file?path=${filePath}`);
+        stackInfo.fileContent.set(filePath, await response.text());
+      } catch {
+        stackInfo.fileContent.set(filePath, `<Unable to read "${filePath}">`);
+      }
     }
     return stackInfo.fileContent.get(filePath)!;
   }, [stackInfo, selectedFrame], '');
diff --git a/packages/trace-viewer/src/ui/workbench.tsx b/packages/trace-viewer/src/ui/workbench.tsx
index 8358896b69..6be206122d 100644
--- a/packages/trace-viewer/src/ui/workbench.tsx
+++ b/packages/trace-viewer/src/ui/workbench.tsx
@@ -36,12 +36,23 @@ export const Workbench: React.FunctionComponent<{
   output?: React.ReactElement,
   rightToolbar?: React.ReactElement[],
 }> = ({ model, output, rightToolbar }) => {
-  const [selectedAction, setSelectedAction] = React.useState<ActionTraceEvent | undefined>();
+  const [selectedAction, setSelectedAction] = React.useState<ActionTraceEvent | undefined>(undefined);
   const [highlightedAction, setHighlightedAction] = React.useState<ActionTraceEvent | undefined>();
   const [selectedNavigatorTab, setSelectedNavigatorTab] = React.useState<string>('actions');
   const [selectedPropertiesTab, setSelectedPropertiesTab] = React.useState<string>(output ? 'output' : 'call');
   const activeAction = model ? highlightedAction || selectedAction : undefined;
 
+  React.useEffect(() => {
+    if (selectedAction)
+      return;
+    const failedAction = model?.actions.find(a => a.error);
+    if (failedAction)
+      setSelectedAction(failedAction);
+    // In the UI mode, selecting the first error should reveal source.
+    if (output)
+      setSelectedPropertiesTab('source');
+  }, [model, output, selectedAction, setSelectedAction, setSelectedPropertiesTab]);
+
   const { errors, warnings } = activeAction ? modelUtil.stats(activeAction) : { errors: 0, warnings: 0 };
   const consoleCount = errors + warnings;
   const networkCount = activeAction ? modelUtil.resourcesForAction(activeAction).length : 0;