diff --git a/frontend/src/ParameterTable.tsx b/frontend/src/ParameterTable.tsx
index 640cd46..36b5d15 100644
--- a/frontend/src/ParameterTable.tsx
+++ b/frontend/src/ParameterTable.tsx
@@ -299,12 +299,20 @@ export function ParameterTable({
   };
 
   useEffect(() => {
-    const dismissOnViewportChange = () => dismissHelpPreview();
-    window.addEventListener("scroll", dismissOnViewportChange, true);
-    window.addEventListener("resize", dismissOnViewportChange);
+    const dismissOnScroll = () => {
+      // Programmatic hover may scroll a lower row into view after mouseenter.
+      // Keep that row's pending preview alive; mouseleave will still cancel it
+      // if scrolling moves the pointer outside the name cell.
+      if (helpPreviewTimerRef.current === null) {
+        helpPreviewAnchorRef.current = null;
+        setHelpPreview(null);
+      }
+    };
+    window.addEventListener("scroll", dismissOnScroll, true);
+    window.addEventListener("resize", dismissHelpPreview);
     return () => {
-      window.removeEventListener("scroll", dismissOnViewportChange, true);
-      window.removeEventListener("resize", dismissOnViewportChange);
+      window.removeEventListener("scroll", dismissOnScroll, true);
+      window.removeEventListener("resize", dismissHelpPreview);
       if (helpPreviewTimerRef.current !== null) {
         window.clearTimeout(helpPreviewTimerRef.current);
         helpPreviewTimerRef.current = null;