diff --git a/ui/src/views/Forecast.jsx b/ui/src/views/Forecast.jsx
index 26d21ce..ca27135 100644
--- a/ui/src/views/Forecast.jsx
+++ b/ui/src/views/Forecast.jsx
@@ -1069,7 +1069,7 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
       grid.resetAutoSize()
       await grid.draw({ invalid_columns: true })
 
-      await fitRowLabels(viewer, grid)
+      await fitRowLabels(grid)
 
       // Widths are not part of ViewConfig, so persist the layout to keep the
       // saved copy in step with what is on screen.
@@ -1081,47 +1081,53 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
     }
   }
 
-  // Pin the row-label column wide enough for the labels it shows.
+  // Pin the row-label columns wide enough for the labels they show.
   //
   // Measured with a canvas rather than the DOM: the cell is clipped, so reading
-  // its box back gives the width it was allotted, not the width of its text --
+  // its box back gives the width it was allotted, not the width of its text —
   // the same circularity that stops headers sizing themselves.
   //
-  // __ROW_PATH__ is the key restore_column_size_overrides special-cases for this
-  // column, and an override is what survives every subsequent draw, which is
-  // exactly why overrides were defeating resetAutoSize in the first place.
-  async function fitRowLabels(viewer, grid) {
+  // Set by column *index* through regular-table's own saveColumnSizes /
+  // restoreColumnSizes, not as a plugin_config column_size_override. The override
+  // path maps the key "__ROW_PATH__" to index tree_header_offset - 1, which with
+  // two group_by levels is index 2 — the first data column, not a row label.
+  // Pinning that was doing nothing visible because that column is the
+  // grand-total one, which the stylesheet hides.
+  async function fitRowLabels(grid) {
     const cells = [...grid.querySelectorAll('tbody th')]
     if (cells.length === 0) return
 
-    const probe = cells[0]
-    const style = getComputedStyle(probe)
+    const style = getComputedStyle(cells[0])
     const ctx = (fitRowLabels._ctx ||= document.createElement('canvas').getContext('2d'))
     ctx.font = `${style.fontWeight} ${style.fontSize} ${style.fontFamily}`
-
-    // Indentation is real width: a tree label sits inside a flex container with
-    // the expand control beside it, so measure from the cell's left edge.
     const padding = parseFloat(style.paddingLeft) + parseFloat(style.paddingRight)
-    let widest = 0
+
+    // One width per row-header column, keyed by the rt-col-N the cell carries.
+    const widest = new Map()
     for (const cell of cells) {
+      const col = [...cell.classList]
+        .map(c => /^rt-col-(\d+)$/.exec(c))
+        .find(Boolean)
+      if (!col) continue
+      const idx = Number(col[1])
       const text = (cell.textContent || '').trim()
       if (!text) continue
-      const indent = cell.querySelector('span.rt-tree-container')
-        ? (parseFloat(getComputedStyle(cell.firstElementChild).paddingLeft) || 0)
-        : 0
-      widest = Math.max(widest, ctx.measureText(text).width + indent)
+      // Tree indentation occupies real width, so it counts toward the fit.
+      const inner = cell.querySelector('span.rt-tree-container')
+      const indent = inner ? (parseFloat(getComputedStyle(inner).paddingLeft) || 0) : 0
+      const w = ctx.measureText(text).width + indent
+      widest.set(idx, Math.max(widest.get(idx) ?? 0, w))
     }
-    if (widest === 0) return
+    if (widest.size === 0) return
 
-    // A few px over, since canvas metrics and rendered text differ slightly with
-    // font fallback and letter-spacing.
-    const width = Math.ceil(widest + padding + 8)
-
-    const { table: _t, ...cfg } = await viewer.save()
-    const pc = { ...(cfg.plugin_config || {}) }
-    pc.columns = { ...(pc.columns || {}) }
-    pc.columns.__ROW_PATH__ = { ...(pc.columns.__ROW_PATH__ || {}), column_size_override: width }
-    await viewer.restore({ ...cfg, plugin_config: pc })
+    const sizes = { ...grid.saveColumnSizes() }
+    for (const [idx, w] of widest) {
+      // A few px over: canvas metrics and rendered text differ slightly with font
+      // fallback and letter-spacing.
+      sizes[idx] = Math.ceil(w + padding + 8)
+    }
+    grid.restoreColumnSizes(sizes)
+    await grid.draw({ invalid_columns: true })
   }
 
   const GRID_CSS = `