diff --git a/ui/src/views/Forecast.jsx b/ui/src/views/Forecast.jsx
index 382a3db..2da34f5 100644
--- a/ui/src/views/Forecast.jsx
+++ b/ui/src/views/Forecast.jsx
@@ -955,21 +955,25 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
 
   // Size every column to its contents.
   //
-  // The datagrid measures content on its own -- draw() calls
-  // regular_table.resetAutoSize() when _reset_column_size is set -- but the reset
-  // is immediately undone:
+  // Values fit on their own: draw() calls regular_table.resetAutoSize(), which
+  // clears the width caches so the next draw measures cells and sets each
+  // column's min-width from the result. The complication is that the plugin's own
+  // draw saves the *live* widths first and restores them immediately after the
+  // reset, so going through it preserves whatever the columns already are. Hence
+  // driving regular_table directly.
   //
-  //     const old_sizes = save_column_size_overrides.call(this);   // live widths
-  //     ... if (this._reset_column_size) { resetAutoSize() }
-  //     restore_column_size_overrides.call(this, old_sizes);       // straight back
+  // Two things that measurement will never fix:
   //
-  // and old_sizes comes from regular_table.saveColumnSizes(), the *live* widths,
-  // not from plugin_config. So every draw preserves whatever the columns are
-  // currently at, and clearing the config releases nothing. Setting the flag and
-  // going through the plugin's draw cannot work for the same reason.
+  //   - Group headers are excluded on purpose. pro.css says so:
+  //       /* Header groups should overflow and not contribute to auto-sizing. */
+  //       thead tr:not(.rt-autosize) th { overflow: hidden; max-width: 0px; }
+  //     Only the leaf header row participates. Letting a group label set width
+  //     would widen every column beneath it, so this is left alone -- with the
+  //     ordinal prefix in front, "01 - Prior…" still reads when truncated.
   //
-  // So drive regular_table directly: drop the cached sizes, reset, and draw. It is
-  // the same draw the plugin calls, without the save/restore wrapped around it.
+  //   - The row-label column measures its *header*, which for row headers is a
+  //     blank corner cell, so it never reflects the labels underneath. That one
+  //     is worth fixing, and is what fitRowLabels does below.
   async function fitColumns() {
     const viewer = viewerRef.current
     if (!viewer) return
@@ -987,6 +991,8 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
       grid.resetAutoSize()
       await grid.draw({ invalid_columns: true })
 
+      await fitRowLabels(viewer, grid)
+
       // Widths are not part of ViewConfig, so persist the layout to keep the
       // saved copy in step with what is on screen.
       const cfg = await captureConfig()
@@ -997,21 +1003,49 @@ export default function Forecast({ sources = [], sourceId, versions = [], versio
     }
   }
 
-  // In rollup mode the datagrid emits a grand-total column group as well as the
-  // subtotals. The subtotals are the point -- they are what per-branch collapse
-  // needs -- but the grand total sums across the split, and when the split is
-  // Prior Year / Plan / Forecast that sum is meaningless and reads as a real
-  // figure to anyone scanning the sheet.
+  // Pin the row-label column wide enough for the labels it shows.
   //
-  // The engine cannot separate them: t_totals is { BEFORE, HIDDEN, AFTER }, and in
-  // a rollup the grand total *is* the root of the hierarchy that produces the
-  // subtotals. So it is hidden rather than suppressed -- the view still computes
-  // it, it is simply not painted.
+  // 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 --
+  // the same circularity that stops headers sizing themselves.
   //
-  // psp-split-total marks it and psp-split-subtotal marks the subtotals, so this
-  // survives adding measures or rearranging the pivot, unlike hiding by position.
-  // The rule has to live inside the plugin's shadow root; a document stylesheet
-  // cannot reach it.
+  // __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) {
+    const cells = [...grid.querySelectorAll('tbody th')]
+    if (cells.length === 0) return
+
+    const probe = cells[0]
+    const style = getComputedStyle(probe)
+    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
+    for (const cell of cells) {
+      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)
+    }
+    if (widest === 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 GRID_CSS = `
     /* Let headers and row labels size their own column.
      *