diff --git a/frontend/src/components/pageEditor/BulkSelectionPanel.module.css b/frontend/src/components/pageEditor/BulkSelectionPanel.module.css
index ca40cdc96..ca4e02b08 100644
--- a/frontend/src/components/pageEditor/BulkSelectionPanel.module.css
+++ b/frontend/src/components/pageEditor/BulkSelectionPanel.module.css
@@ -146,9 +146,9 @@
 .selectedList {
   max-height: 8rem;
   overflow: auto;
-  border: 0.0625rem solid var(--mantine-color-gray-3);
-  border-radius: 0.25rem;
-  padding: 0.5rem;
+  background-color: var(--mantine-color-gray-0);
+  border-radius: 0.5rem;
+  padding: 0.5rem 0.75rem;
   margin-top: 0.5rem;
   min-width: 24rem;
 }
@@ -232,3 +232,30 @@
   flex-shrink: 0;
 }
 
+/* Error helper text above the input */
+.errorText {
+  margin-top: 0.25rem;
+  color: var(--mantine-color-red-6);
+}
+
+/* Dark-mode adjustments */
+::global([data-mantine-color-scheme='dark']) .selectedList {
+  background-color: var(--mantine-color-dark-6);
+}
+
+/* Small screens: allow the section to shrink instead of enforcing a large min width */
+@media (max-width: 480px) {
+  .panelGroup,
+  .selectedList,
+  .advancedSection,
+  .panelContainer {
+    min-width: 0;
+  }
+}
+
+/* Outermost panel container scrolling */
+.panelContainer {
+  max-height: 95vh;
+  overflow: auto;
+}
+
diff --git a/frontend/src/components/pageEditor/BulkSelectionPanel.tsx b/frontend/src/components/pageEditor/BulkSelectionPanel.tsx
index dc3b12937..6449062a6 100644
--- a/frontend/src/components/pageEditor/BulkSelectionPanel.tsx
+++ b/frontend/src/components/pageEditor/BulkSelectionPanel.tsx
@@ -1,9 +1,10 @@
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
 import { Group, TextInput, Button, Text, NumberInput, Flex } from '@mantine/core';
 import LocalIcon from '../shared/LocalIcon';
 import { Tooltip } from '../shared/Tooltip';
 import { usePageSelectionTips } from '../tooltips/usePageSelectionTips';
 import classes from './BulkSelectionPanel.module.css';
+import { parseSelectionWithDiagnostics } from '../../utils/bulkselection/parseSelection';
 import {
   appendExpression,
   insertOperatorSmart,
@@ -38,10 +39,26 @@ const BulkSelectionPanel = ({
   const [firstNError, setFirstNError] = useState<string | null>(null);
   const [lastNError, setLastNError] = useState<string | null>(null);
   const [rangeError, setRangeError] = useState<string | null>(null);
+  const [syntaxError, setSyntaxError] = useState<string | null>(null);
 
   const maxPages = displayDocument?.pages?.length ?? 0;
 
 
+  // Validate input syntax and show lightweight feedback
+  useEffect(() => {
+    const text = (csvInput || '').trim();
+    if (!text) {
+      setSyntaxError(null);
+      return;
+    }
+    try {
+      const { warning } = parseSelectionWithDiagnostics(text, maxPages);
+      setSyntaxError(warning ? 'There is a syntax issue. See Page Selection tips for help.' : null);
+    } catch {
+      setSyntaxError('There is a syntax issue. See Page Selection tips for help.');
+    }
+  }, [csvInput, maxPages]);
+
   const applyExpression = (expr: string) => {
     const nextInput = appendExpression(csvInput, expr);
     setCsvInput(nextInput);
@@ -62,7 +79,10 @@ const BulkSelectionPanel = ({
   };
 
   return (
-    <>
+    <div className={classes.panelContainer}>
+      {syntaxError && (
+        <Text size="xs" className={classes.errorText}>{syntaxError}</Text>
+      )}
       <Group className={classes.panelGroup}>
         <TextInput
           value={csvInput}
@@ -106,7 +126,6 @@ const BulkSelectionPanel = ({
                 </Flex>
               </Tooltip>
           }
-          onBlur={() => onUpdatePagesFromCSV()}
           onKeyDown={(e) => e.key === 'Enter' && onUpdatePagesFromCSV()}
           className={classes.textInput}
         />
@@ -364,7 +383,7 @@ const BulkSelectionPanel = ({
           </div>
         </div>
       )}
-      </>
+      </div>
   );
 };