diff --git a/ui/src/views/Forecast.jsx b/ui/src/views/Forecast.jsx
index f73e983..fa1a2ce 100644
--- a/ui/src/views/Forecast.jsx
+++ b/ui/src/views/Forecast.jsx
@@ -659,7 +659,7 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
       // the named table in time.
       await viewer.load(tableRef.current)
       viewer.setAttribute('theme', dark ? 'Pro Dark' : 'Pro Light')
-      hideSplitTotal()
+      if (!hideSplitTotal()) setTimeout(hideSplitTotal, 400)
 
       // restore last-used layout or build default
       // Strip cfg.table — table is already loaded by reference above; a stale name
@@ -841,15 +841,36 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
     }
   `
 
+  // Find the grid wherever it is. Guessing the nesting was wrong once already --
+  // the plugin element's own shadow root is not where the cells live -- so locate
+  // regular-table by walking through shadow roots, then inject into whatever root
+  // actually contains it via getRootNode(). No structural assumption survives a
+  // Perspective upgrade; this one asks the DOM instead.
+  function deepFindRegularTable(node, depth = 0) {
+    if (!node || depth > 12) return null
+    if (node.tagName === 'REGULAR-TABLE') return node
+    for (const child of node.children || []) {
+      const hit = deepFindRegularTable(child, depth + 1)
+      if (hit) return hit
+    }
+    if (node.shadowRoot) return deepFindRegularTable(node.shadowRoot, depth + 1)
+    return null
+  }
+
   function hideSplitTotal() {
     const viewer = viewerRef.current
-    const root = viewer?.shadowRoot
-      ?.querySelector('perspective-viewer-datagrid')?.shadowRoot
-    if (!root || root.getElementById?.('pf-hide-split-total')) return
+    if (!viewer) return
+    const grid = deepFindRegularTable(viewer)
+    // The grid is built asynchronously after load, so it may not exist yet.
+    // Retried from the config-update handler, and once on a short delay.
+    if (!grid) return false
+    const root = grid.getRootNode()
+    if (!root || root.querySelector?.('#pf-hide-split-total')) return true
     const style = document.createElement('style')
     style.id = 'pf-hide-split-total'
     style.textContent = HIDE_SPLIT_TOTAL_CSS
-    root.appendChild(style)
+    ;(root.appendChild ? root : document.head).appendChild(style)
+    return true
   }
 
   // Row depth is a ViewConfig field, so it is set through restore() rather than